diff --git a/Cargo.lock b/Cargo.lock
index c113248b6..9ca4e6a0b 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1259,17 +1259,6 @@ dependencies = [
  "num-traits",
 ]
 
-[[package]]
-name = "num-iter"
-version = "0.1.42"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "b2021c8337a54d21aca0d59a92577a029af9431cb59b909b03252b9c164fad59"
-dependencies = [
- "autocfg",
- "num-integer",
- "num-traits",
-]
-
 [[package]]
 name = "num-rational"
 version = "0.4.0"
@@ -2048,7 +2037,6 @@ dependencies = [
  "num-bigint",
  "num-complex",
  "num-integer",
- "num-iter",
  "num-rational",
  "num-traits",
  "num_cpus",
diff --git a/vm/Cargo.toml b/vm/Cargo.toml
index e1ff9a6a4..d983ba6c3 100644
--- a/vm/Cargo.toml
+++ b/vm/Cargo.toml
@@ -38,7 +38,6 @@ num-bigint = { version = "0.4.0", features = ["serde"] }
 num-traits = "0.2.8"
 num-integer = "0.1.41"
 num-rational = "0.4.0"
-num-iter = "0.1.39"
 rand = "0.8"
 rand_core = "0.6"
 getrandom = { version = "0.2", features = ["js"] }
diff --git a/vm/src/stdlib/math.rs b/vm/src/stdlib/math.rs
index fcd100e87..a2cd36cf8 100644
--- a/vm/src/stdlib/math.rs
+++ b/vm/src/stdlib/math.rs
@@ -473,13 +473,20 @@ fn math_fsum(iter: PyIterable<IntoPyFloat>, vm: &VirtualMachine) -> PyResult<f64
 
 fn math_factorial(value: PyIntRef, vm: &VirtualMachine) -> PyResult<BigInt> {
     let value = value.borrow_value();
+    let one = BigInt::one();
     if value.is_negative() {
         return Err(vm.new_value_error("factorial() not defined for negative values".to_owned()));
-    } else if *value <= BigInt::one() {
-        return Ok(BigInt::from(1u64));
+    } else if *value <= one {
+        return Ok(one);
     }
-    let ret: BigInt = num_iter::range_inclusive(BigInt::from(1u64), value.clone()).product();
-    Ok(ret)
+    // start from 2, since we know that value > 1 and 1*2=2
+    let mut current = one + 1;
+    let mut product = BigInt::from(2u8);
+    while current < *value {
+        current += 1;
+        product *= &current;
+    }
+    Ok(product)
 }
 
 fn math_modf(x: IntoPyFloat) -> (f64, f64) {