diff --git a/builtin/bigint.mbt b/builtin/bigint.mbt
index 054990e1c..cd2997df4 100644
--- a/builtin/bigint.mbt
+++ b/builtin/bigint.mbt
@@ -61,9 +61,9 @@ let karatsuba_threshold = 50
 
 // Useful bigints
 
-let zero : BigInt = 0N
+let zero : BigInt = { limbs: [0], sign: Positive, len: 1 }
 
-let one : BigInt = 1N
+let one : BigInt = { limbs: [1], sign: Positive, len: 1 }
 
 // Conversion Functions
 
@@ -72,10 +72,79 @@ pub fn BigInt::from_int(n : Int) -> BigInt {
   BigInt::from_int64(n.to_int64())
 }
 
+pub fn BigInt::equal_int64(self : BigInt, n : Int64) -> Bool {
+  // Check if the sign of BigInt matches the sign of n
+  if (self.sign == Negative && n >= 0) || (self.sign == Positive && n < 0) {
+    return false
+  }
+
+  // Handle zero case
+  if n == 0L {
+    return self.is_zero()
+  }
+
+  // Convert n to positive for comparison
+  let mut m = if n < 0L { -n } else { n }
+  let mut i = 0
+
+  // Compare limbs
+  while m > 0L {
+    if i >= self.len || self.limbs[i] != (m % radix).to_int() {
+      return false
+    }
+    m /= radix
+    i += 1
+  }
+
+  // Ensure all remaining limbs in BigInt are zero
+  while i < self.len {
+    if self.limbs[i] != 0 {
+      return false
+    }
+    i += 1
+  }
+  true
+}
+
+pub fn BigInt::equal_int(self : BigInt, other : Int) -> Bool {
+  // Check if the sign of BigInt matches the sign of other
+  if (self.sign == Negative && other >= 0) ||
+    (self.sign == Positive && other < 0) {
+    return false
+  }
+
+  // Handle zero case
+  if other == 0 {
+    return self.is_zero()
+  }
+
+  // Convert other to positive for comparison
+  let mut m = if other < 0 { -other } else { other }
+  let mut i = 0
+
+  // Compare limbs
+  while m > 0 {
+    if i >= self.len || self.limbs[i] != m % radix.to_int() {
+      return false
+    }
+    m /= radix.to_int()
+    i += 1
+  }
+
+  // Ensure all remaining limbs in BigInt are zero
+  while i < self.len {
+    if self.limbs[i] != 0 {
+      return false
+    }
+    i += 1
+  }
+  true
+}
+
 /// Convert an Int64 to a BigInt.
 pub fn BigInt::from_int64(n : Int64) -> BigInt {
   if n == 0L {
-    return { limbs: FixedArray::make(1, 0), sign: Positive, len: 1 }
+    return zero
   }
   let limbs = FixedArray::make(64 / radix_bit_len, 0U)
   let mut m = (if n < 0L { -n } else { n }).to_uint64()
diff --git a/builtin/bigint_wbtest.mbt b/builtin/bigint_wbtest.mbt
index 7ce5cfd01..40971ed69 100644
--- a/builtin/bigint_wbtest.mbt
+++ b/builtin/bigint_wbtest.mbt
@@ -20,6 +20,47 @@ impl Show for MyBigInt with output(self, logger) {
   )
 }
 
+test {
+  inspect!(
+    MyBigInt(BigInt::from_int64(0)),
+    content="{limbs : [0], sign : Positive, len : 1 }",
+  )
+  inspect!(
+    MyBigInt(BigInt::from_int64(1)),
+    content="{limbs : [1, 0, 0, 0], sign : Positive, len : 1 }",
+  )
+  inspect!(MyBigInt(1), content="{limbs : [1, 0], sign : Positive, len : 1 }")
+  inspect!(
+    MyBigInt(0xffff_ffff),
+    content="{limbs : [65535, 65535, 0, 0], sign : Positive, len : 2 }",
+  )
+  inspect!(
+    MyBigInt(0xffff_ffff_ffff_ffff),
+    content="{limbs : [65535, 65535, 65535, 65535, 0, 0], sign : Positive, len : 4 }",
+  )
+}
+
+test "equal_int64" {
+  assert_eq!(BigInt::from_int64(0).equal_int64(0), true)
+  assert_eq!(BigInt::from_int64(1).equal_int64(1), true)
+  assert_eq!(BigInt::from_int64(0xffff_ffff).equal_int64(0xffff_ffff), true)
+  inspect!(BigInt::from_int64(0xffff_ffff_ffff_ffff), content="-1")
+  inspect!(0xffff_ffff_ffff_ffffN, content="18446744073709551615")
+  assert_eq!(
+    BigInt::from_int64(0xffff_ffff_ffff_ffff).equal_int64(0xffff_ffff_ffff_ffff),
+    true,
+  )
+}
+
+test "equal_int" {
+  assert_eq!(BigInt::from_int64(0).equal_int(0), true)
+  assert_eq!(BigInt::from_int64(1).equal_int(1), true)
+  // overflow
+  assert_eq!(BigInt::from_int64(0xffff_ffff).equal_int(0xffff_ffff), false)
+  assert_eq!(BigInt::from_int64(0x7fff_ffff).equal_int(0x7fff_ffff), true)
+  assert_eq!(BigInt::from_int64(0x8fff_ffff).equal_int(0x8fff_ffff), false)
+}
+
 test "debug_string" {
   let buf = Buffer::new()
   let v : Array[MyBigInt] = [0, 1, 2, 3, 4, -0, -1, -2, -3]
diff --git a/builtin/builtin.mbti b/builtin/builtin.mbti
index c2b4888f0..93e198b92 100644
--- a/builtin/builtin.mbti
+++ b/builtin/builtin.mbti
@@ -129,6 +129,8 @@ type BigInt
 impl BigInt {
   asr(Self, Int) -> Self
   compare(Self, Self) -> Int
+  equal_int(Self, Int) -> Bool
+  equal_int64(Self, Int64) -> Bool
   from_hex(String) -> Self
   from_int(Int) -> Self
   from_int64(Int64) -> Self