Prime factor of 300 000 000 000?

Question

I need to find out the prime factors of over 300 billion. I have a function that is adding to the list of them...very slowly! It has been running for about an hour now and i

Answer 1

Just to expand/improve slightly on the "only test odd numbers that don't end in 5" suggestions...

All primes greater than 3 are either one more or one less than a multiple of 6 (6x + 1 or 6x - 1 for integer values of x).