Show using Fermat's Little Theorem that 66013 is not prime.
If: 2^(66,013 - 1) mod (66,013) = 1, it is probable prime, otherwise it is composite.
But, 2^(66,012) mod (66,013) =11,626. Therefore, it is not prime!
Whatever base between 2 and 66,013 you may try, you will get a remainder > 1.
