diff --git a/src/is_prime.rs b/src/is_prime.rs
index 5780bd1..9a9b0d4 100644
--- a/src/is_prime.rs
+++ b/src/is_prime.rs
@@ -11,6 +11,10 @@ pub mod is_prime {
         if BigUint::from(4u8) > *number  {
             return true;
         }
+
+        if number.sqrt().pow(2) == *number {
+            return false;
+        }
     
         let two = BigUint::from(2u8);
     
@@ -22,7 +26,7 @@ pub mod is_prime {
             let one = BigUint::from(1u8);
             let zero = BigUint::from(0u8);
             
-            let sqrtnum = number.sqrt()+&one;
+            let sqrtnum = number.sqrt()+&one; //fake ceil function
             let mut is_prime = true;
             loop {
                 i = i + &one;