diff --git a/crates/oxide_kernel/src/builtin.rs b/crates/oxide_kernel/src/builtin.rs
index 5b10c6a..52cd1e4 100644
--- a/crates/oxide_kernel/src/builtin.rs
+++ b/crates/oxide_kernel/src/builtin.rs
@@ -66,6 +66,15 @@ pub struct StringMethods {
     pub search: *const (),
 }
 
+pub struct NumberMethods {
+    pub is_nan: *const (),
+    pub is_finite: *const (),
+    pub parse_int: *const (),
+    pub parse_float: *const (),
+    pub to_string: *const (),
+    pub to_fixed: *const (),
+}
+
 pub struct BuiltinWorld {
     pub object_proto: P<JsObject>,
     pub array_proto: P<JsObject>,
@@ -557,6 +566,61 @@ impl BuiltinWorld {
         );
     }
 
+    pub fn bind_number_methods(
+        &self,
+        methods: &NumberMethods,
+        string_forge: &StringForge,
+        shape_forge: &ShapeForge,
+    ) {
+        let ctor_ptr = P::as_ptr(&self.number_constructor) as *mut JsObject;
+        let ctor = unsafe { &mut *ctor_ptr };
+        let proto_ptr = P::as_ptr(&self.number_proto) as *mut JsObject;
+        let proto = unsafe { &mut *proto_ptr };
+
+        let _ = Self::bind_method(ctor, shape_forge, string_forge, "isNaN", methods.is_nan, 1);
+        let _ = Self::bind_method(
+            ctor,
+            shape_forge,
+            string_forge,
+            "isFinite",
+            methods.is_finite,
+            1,
+        );
+        let _ = Self::bind_method(
+            ctor,
+            shape_forge,
+            string_forge,
+            "parseInt",
+            methods.parse_int,
+            1,
+        );
+        let _ = Self::bind_method(
+            ctor,
+            shape_forge,
+            string_forge,
+            "parseFloat",
+            methods.parse_float,
+            1,
+        );
+
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "toString",
+            methods.to_string,
+            0,
+        );
+        let _ = Self::bind_method(
+            proto,
+            shape_forge,
+            string_forge,
+            "toFixed",
+            methods.to_fixed,
+            0,
+        );
+    }
+
     pub fn bind_method(
         proto: &mut JsObject,
         shape_forge: &ShapeForge,
diff --git a/crates/oxide_vm/src/builtins/mod.rs b/crates/oxide_vm/src/builtins/mod.rs
index 276aea7..9abc4fd 100644
--- a/crates/oxide_vm/src/builtins/mod.rs
+++ b/crates/oxide_vm/src/builtins/mod.rs
@@ -1,5 +1,6 @@
 pub mod array;
 pub mod error;
 pub mod global;
+pub mod number;
 pub mod object;
 pub mod string;
diff --git a/crates/oxide_vm/src/builtins/number.rs b/crates/oxide_vm/src/builtins/number.rs
new file mode 100644
index 0000000..6f2032c
--- /dev/null
+++ b/crates/oxide_vm/src/builtins/number.rs
@@ -0,0 +1,169 @@
+use oxide_types::value::JsValue;
+
+use crate::coercion;
+use crate::native::NativeResult;
+use crate::vm::Vm;
+
+pub fn number_constructor(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let n = if args.len() > 1 {
+        coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref())
+    } else {
+        0.0
+    };
+    if n.fract() == 0.0 && n.is_finite() && n >= i32::MIN as f64 && n <= i32::MAX as f64 {
+        Ok(JsValue::int(n as i32))
+    } else {
+        Ok(JsValue::float(n))
+    }
+}
+
+pub fn number_is_nan(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    if args.len() < 2 {
+        return Ok(JsValue::bool(false));
+    }
+    let val = vm.reg(args[1]);
+    if val.is_double() {
+        Ok(JsValue::bool(val.as_double().is_nan()))
+    } else {
+        Ok(JsValue::bool(false))
+    }
+}
+
+pub fn number_is_finite(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    if args.len() < 2 {
+        return Ok(JsValue::bool(false));
+    }
+    let val = vm.reg(args[1]);
+    if val.is_int() {
+        return Ok(JsValue::bool(true));
+    }
+    if val.is_double() {
+        return Ok(JsValue::bool(val.as_double().is_finite()));
+    }
+    let n = coercion::to_number(val, vm.kernel().string_forge().as_ref());
+    Ok(JsValue::bool(n.is_finite()))
+}
+
+pub fn number_parse_int(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    if args.len() < 2 {
+        return Ok(JsValue::float(f64::NAN));
+    }
+    let sf = vm.kernel().string_forge().as_ref();
+    let s = coercion::to_string(sf, vm.reg(args[1]));
+    let s = s.trim();
+
+    if s.is_empty() {
+        return Ok(JsValue::float(f64::NAN));
+    }
+
+    let radix = if args.len() > 2 {
+        let r = coercion::to_number(vm.reg(args[2]), sf) as i32;
+        if r == 0 {
+            10
+        } else {
+            r.clamp(2, 36)
+        }
+    } else {
+        10
+    };
+
+    let (rest, hex) = if s.starts_with("0x") || s.starts_with("0X") {
+        if radix == 16 || radix == 0 || (args.len() <= 2) {
+            (s[2..].to_string(), true)
+        } else {
+            (s.to_string(), false)
+        }
+    } else {
+        (s.to_string(), false)
+    };
+
+    let actual_radix = if hex { 16u32 } else { radix as u32 };
+
+    if let Ok(n) = i32::from_str_radix(&rest, actual_radix) {
+        return Ok(JsValue::int(n));
+    }
+
+    Ok(JsValue::float(f64::NAN))
+}
+
+pub fn number_parse_float(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    if args.len() < 2 {
+        return Ok(JsValue::float(f64::NAN));
+    }
+    let sf = vm.kernel().string_forge().as_ref();
+    let s = coercion::to_string(sf, vm.reg(args[1]));
+    let s = s.trim();
+
+    if s.is_empty() {
+        return Ok(JsValue::float(f64::NAN));
+    }
+
+    match fast_float::parse::<f64, _>(&s) {
+        Ok(v) => Ok(JsValue::float(v)),
+        Err(_) => Ok(JsValue::float(f64::NAN)),
+    }
+}
+
+pub fn number_to_string(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let n = coercion::to_number(vm.reg(args[0]), vm.kernel().string_forge().as_ref());
+    let radix = if args.len() > 1 {
+        let r = coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as u32;
+        r.clamp(2, 36)
+    } else {
+        10u32
+    };
+
+    if radix == 10 {
+        if n.is_nan() {
+            return Ok(vm.intern("NaN"));
+        }
+        if n.is_infinite() {
+            if n.is_sign_positive() {
+                return Ok(vm.intern("Infinity"));
+            }
+            return Ok(vm.intern("-Infinity"));
+        }
+        if n.fract() == 0.0 && n >= i32::MIN as f64 && n <= i32::MAX as f64 {
+            return Ok(vm.intern(&(n as i64).to_string()));
+        }
+        let mut buf = ryu::Buffer::new();
+        Ok(vm.intern(buf.format(n)))
+    } else {
+        if n.is_nan() {
+            return Ok(vm.intern("NaN"));
+        }
+        let nn = n as i64;
+        let mut result = String::new();
+        let mut value = nn.abs();
+        if value == 0 {
+            result.push('0');
+        } else {
+            let chars = "0123456789abcdefghijklmnopqrstuvwxyz";
+            let mut digits = Vec::new();
+            while value > 0 {
+                digits.push(chars.as_bytes()[(value % radix as i64) as usize] as char);
+                value /= radix as i64;
+            }
+            for ch in digits.iter().rev() {
+                result.push(*ch);
+            }
+        }
+        if nn < 0 {
+            result.insert(0, '-');
+        }
+        Ok(vm.intern(&result))
+    }
+}
+
+pub fn number_to_fixed(vm: &mut Vm, args: &[u8]) -> NativeResult {
+    let n = coercion::to_number(vm.reg(args[0]), vm.kernel().string_forge().as_ref());
+    let digits = if args.len() > 1 {
+        coercion::to_number(vm.reg(args[1]), vm.kernel().string_forge().as_ref()) as usize
+    } else {
+        0usize
+    }
+    .min(20);
+
+    let formatted = format!("{:.digits$}", n);
+    Ok(vm.intern(&formatted))
+}
diff --git a/crates/oxide_vm/src/vm.rs b/crates/oxide_vm/src/vm.rs
index 48be491..1cd36f6 100644
--- a/crates/oxide_vm/src/vm.rs
+++ b/crates/oxide_vm/src/vm.rs
@@ -8,7 +8,9 @@ use oxide_compiler::opcode::{self, OpCode};
 
 use crate::coercion;
 use crate::native::NativeFn;
-use oxide_kernel::builtin::{ArrayMethods, ErrorMethods, ObjectMethods, StringMethods};
+use oxide_kernel::builtin::{
+    ArrayMethods, ErrorMethods, NumberMethods, ObjectMethods, StringMethods,
+};
 use oxide_kernel::kernel::{KernelConfig, OxideKernel};
 use oxide_kernel::prop_forge::PropTemplate;
 use oxide_kernel::shape_forge::EMPTY_SHAPE_ID;
@@ -65,8 +67,7 @@ pub fn init_kernel_builtins(kernel: &Arc<OxideKernel>) {
     let cur_count = global.prop_count();
     global.set_shape_id(obj_shape);
     global.set_prop_count(cur_count + 1);
-    let bump = bumpalo::Bump::new();
-    global.set_prop_expand(cur_count, obj_val, &bump);
+    global.set_prop_expand_heap(cur_count, obj_val);
 
     let _array_methods = ArrayMethods {
         push: crate::builtins::array::array_push as *const (),
@@ -102,8 +103,7 @@ pub fn init_kernel_builtins(kernel: &Arc<OxideKernel>) {
     let cur_count = global.prop_count();
     global.set_shape_id(arr_shape);
     global.set_prop_count(cur_count + 1);
-    let bump2 = bumpalo::Bump::new();
-    global.set_prop_expand(cur_count, arr_val, &bump2);
+    global.set_prop_expand_heap(cur_count, arr_val);
     global.bump_generation();
 
     let error_methods = ErrorMethods {
@@ -128,8 +128,7 @@ pub fn init_kernel_builtins(kernel: &Arc<OxideKernel>) {
     let cur_count = global.prop_count();
     global.set_shape_id(err_shape);
     global.set_prop_count(cur_count + 1);
-    let bump3 = bumpalo::Bump::new();
-    global.set_prop_expand(cur_count, err_val, &bump3);
+    global.set_prop_expand_heap(cur_count, err_val);
     global.bump_generation();
 
     let string_methods = StringMethods {
@@ -167,9 +166,61 @@ pub fn init_kernel_builtins(kernel: &Arc<OxideKernel>) {
     let cur_count = global.prop_count();
     global.set_shape_id(str_shape);
     global.set_prop_count(cur_count + 1);
-    let bump4 = bumpalo::Bump::new();
-    global.set_prop_expand(cur_count, str_val, &bump4);
+    global.set_prop_expand_heap(cur_count, str_val);
     global.bump_generation();
+
+    let number_methods = NumberMethods {
+        is_nan: crate::builtins::number::number_is_nan as *const (),
+        is_finite: crate::builtins::number::number_is_finite as *const (),
+        parse_int: crate::builtins::number::number_parse_int as *const (),
+        parse_float: crate::builtins::number::number_parse_float as *const (),
+        to_string: crate::builtins::number::number_to_string as *const (),
+        to_fixed: crate::builtins::number::number_to_fixed as *const (),
+    };
+    kernel.builtin_world().bind_number_methods(
+        &number_methods,
+        kernel.string_forge().as_ref(),
+        kernel.shape_forge().as_ref(),
+    );
+
+    let si_num = kernel.string_forge().intern("Number").0;
+    let num_shape = kernel.shape_forge().make_shape(global.shape_id(), si_num);
+    let num_val = JsValue::from_js_object(
+        kernel.builtin_world().number_constructor.as_ptr() as *mut JsObject
+    );
+    let cur_count = global.prop_count();
+    global.set_shape_id(num_shape);
+    global.set_prop_count(cur_count + 1);
+    global.set_prop_expand_heap(cur_count, num_val);
+    global.bump_generation();
+
+    {
+        let num_ctor_ptr = kernel.builtin_world().number_constructor.as_ptr() as *mut JsObject;
+        let num_ctor = unsafe { &mut *num_ctor_ptr };
+        num_ctor.set_native_fn(Some(
+            crate::builtins::number::number_constructor as *const (),
+        ));
+        num_ctor.set_native_arg_count(1);
+    }
+
+    let pi_fn = crate::builtins::number::number_parse_int as *const ();
+    let pf_fn = crate::builtins::number::number_parse_float as *const ();
+    let _ = oxide_kernel::builtin::BuiltinWorld::bind_method(
+        global,
+        kernel.shape_forge().as_ref(),
+        kernel.string_forge().as_ref(),
+        "parseInt",
+        pi_fn,
+        1,
+    );
+    let _ = oxide_kernel::builtin::BuiltinWorld::bind_method(
+        global,
+        kernel.shape_forge().as_ref(),
+        kernel.string_forge().as_ref(),
+        "parseFloat",
+        pf_fn,
+        1,
+    );
 }
 
 impl Vm {
@@ -605,6 +656,17 @@ impl Vm {
                                 continue;
                             }
                         }
+                        if val.is_int() || val.is_double() {
+                            let proto_ptr =
+                                self.kernel.builtin_world().number_proto.as_ptr() as *mut JsObject;
+                            let proto = unsafe { &*proto_ptr };
+                            let prop_name_si = self.regs[b].as_string_index();
+                            if let Some(resolved) = self.resolve_property(proto, prop_name_si) {
+                                self.regs[a] = resolved;
+                                self.pc += 1;
+                                continue;
+                            }
+                        }
                         return Err("IC_GET_PROP on non-object".into());
                     }
                     let obj = unsafe { &*obj_ptr };
diff --git a/crates/oxide_vm/tests/builtins_number_tests.rs b/crates/oxide_vm/tests/builtins_number_tests.rs
new file mode 100644
index 0000000..9479825
--- /dev/null
+++ b/crates/oxide_vm/tests/builtins_number_tests.rs
@@ -0,0 +1,100 @@
+use oxide_compiler::compiler::Compiler;
+use oxide_types::value::JsValue;
+use oxide_vm::vm::Vm;
+
+fn eval(vm: &mut Vm, source: &str) -> Result<JsValue, String> {
+    let allocator = oxide_parser::Allocator::default();
+    let program =
+        oxide_parser::parse(&allocator, source).map_err(|e| format!("Parse error: {:?}", e))?;
+    let module = Compiler::new()
+        .compile(&program)
+        .map_err(|e| format!("Compile error: {}", e))?;
+    vm.run(&module)
+}
+
+#[test]
+fn number_is_nan_with_nan() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Number.isNaN(NaN)").unwrap();
+    assert!(result.as_bool());
+}
+
+#[test]
+fn number_is_nan_with_number() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Number.isNaN(42)").unwrap();
+    assert!(!result.as_bool());
+}
+
+#[test]
+fn number_is_finite_with_number() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Number.isFinite(42)").unwrap();
+    assert!(result.as_bool());
+}
+
+#[test]
+fn number_is_finite_with_infinity() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Number.isFinite(1/0)").unwrap();
+    assert!(!result.as_bool());
+}
+
+#[test]
+fn parse_int_decimal() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "parseInt('42')").unwrap();
+    assert_eq!(result.as_int(), 42);
+}
+
+#[test]
+fn parse_int_hex() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "parseInt('0xFF')").unwrap();
+    assert_eq!(result.as_int(), 255);
+}
+
+#[test]
+fn parse_float_decimal() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "parseFloat('3.14')").unwrap();
+    assert!((result.as_double() - 3.14).abs() < 0.001);
+}
+
+#[test]
+fn parse_float_invalid() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "parseFloat('abc')").unwrap();
+    assert!(result.as_double().is_nan());
+}
+
+#[test]
+fn number_constructor() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "Number('42')").unwrap();
+    assert_eq!(result.as_int(), 42);
+}
+
+#[test]
+fn to_string_of_number() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "var n = 42; n.toString()").unwrap();
+    let s = vm
+        .kernel()
+        .string_forge()
+        .lookup(result.as_string_index())
+        .unwrap_or_default();
+    assert_eq!(s, "42");
+}
+
+#[test]
+fn to_fixed_of_number() {
+    let mut vm = Vm::new();
+    let result = eval(&mut vm, "var n = 3.14159; n.toFixed(2)").unwrap();
+    let s = vm
+        .kernel()
+        .string_forge()
+        .lookup(result.as_string_index())
+        .unwrap_or_default();
+    assert_eq!(s, "3.14");
+}