1. The problem statement, all variables and given/known data Use the Fermat test to show that 513 is not a prime number. 2. Relevant equations 3. The attempt at a solution What i have so far is: n=513 Then i pick an 'a' with 1<a<n Let a=8 So i need to compute a^(n-1) mod n -> 8^512 mod 513 If 8^512 is not congruent to 1 mod 513, then i have shown 513 is not a prime number. However i am stuck with how to do this. Any help would be great thanks!