(I'm not sure what forum to put this on: number theory because of factoring, programming because I want to automate it, computers because I don't intend to actually program anything myself, or general because it combines these.) I'm looking for a program that I can use to partially factor numbers that are too large to fully factor (thousands of digits -- 500 to 35,000 bits). I'd like a 'high' chance of finding all factors below 15 digits or so. A program that has trouble with repeated factors (squareful numbers) is inappropriate, as these numbers may well be divisible by the square of a large (> 1e9) prime. I don't know of any that have trouble with these other than prime powers, but I thought I'd mention it just in case. So what's out there?