diff --git a/icicle/utils/utils_kernels.cuh b/icicle/utils/utils_kernels.cuh
index 69838bcff..be4be2003 100644
--- a/icicle/utils/utils_kernels.cuh
+++ b/icicle/utils/utils_kernels.cuh
@@ -34,7 +34,7 @@ namespace utils_internal {
   {
     int tid = blockDim.x * blockIdx.x + threadIdx.x;
     if (tid < n_elements * batch_size) {
-      int scalar_id = tid % n_elements;
+      int64_t scalar_id = tid % n_elements;
       if (bitrev) scalar_id = __brev(scalar_id) >> (32 - logn);
       out_vec[tid] = *(scalar_vec + ((scalar_id * step) % n_scalars)) * in_vec[tid];
     }
diff --git a/wrappers/rust/icicle-core/src/ntt/mod.rs b/wrappers/rust/icicle-core/src/ntt/mod.rs
index 27d512400..04f10ba70 100644
--- a/wrappers/rust/icicle-core/src/ntt/mod.rs
+++ b/wrappers/rust/icicle-core/src/ntt/mod.rs
@@ -208,7 +208,7 @@ macro_rules! impl_ntt_tests {
     (
       $field:ident
     ) => {
-        const MAX_SIZE: u64 = 1 << 16;
+        const MAX_SIZE: u64 = 1 << 17;
         static INIT: OnceLock<()> = OnceLock::new();
 
         #[test]
diff --git a/wrappers/rust/icicle-core/src/ntt/tests.rs b/wrappers/rust/icicle-core/src/ntt/tests.rs
index e2b86bafe..ef7788f00 100644
--- a/wrappers/rust/icicle-core/src/ntt/tests.rs
+++ b/wrappers/rust/icicle-core/src/ntt/tests.rs
@@ -48,7 +48,7 @@ where
     F::ArkEquivalent: FftField,
     <F as FieldImpl>::Config: NTT<F> + GenerateRandom<F>,
 {
-    let test_sizes = [1 << 4, 1 << 16];
+    let test_sizes = [1 << 4, 1 << 17];
     for test_size in test_sizes {
         let ark_domain = GeneralEvaluationDomain::<F::ArkEquivalent>::new(test_size).unwrap();
 
@@ -161,7 +161,7 @@ where
     <F as FieldImpl>::Config: NTT<F> + GenerateRandom<F>,
 {
     let mut seed = test_rng();
-    let test_sizes = [1 << 4, 1 << 16];
+    let test_sizes = [1 << 4, 1 << 17];
     for test_size in test_sizes {
         let coset_generators = [
             F::ArkEquivalent::rand(&mut seed),