diff --git a/src/main.rs b/src/main.rs
index 928af1d..7a97081 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -20,6 +20,14 @@ fn count_prime_factor_exponent(prime: u64, mut nr: u64) -> u64 {
 fn prime_factors(nr: u64, primes: &[u64]) -> u64 {
     let mut num_teilers = 1;
 
+    // safety: nr <= 2.pow(53) must be fulfilled,
+    //         otherwise we have a precision loss
+    assert!(nr <= 2u64.pow(53));
+    #[allow(
+        clippy::cast_sign_loss,
+        clippy::cast_possible_truncation,
+        clippy::cast_precision_loss
+    )]
     let nr_sqrt = (nr as f64).sqrt().ceil() as u64;
 
     for prime in primes {