It's a competition set up with prizes for factoring some 'semiprimes' (numbers with exactly two prime divisors). So unless the challenge organizers had messed u

It's a competition set up with prizes for factoring some 'semiprimes' (numbers with exactly two prime divisors). So unless the challenge organizers had messed up, they were guaranteed this. [1] https://en.wikipedia.org/wiki/RSA_Factoring_Challenge https://en.wikipedia.org/wiki/RSA_Factoring_Challenge