factor 16000000000000002295000000000000003170601
first trying brute force division by small primes
PRIME FACTOR 1249
now trying 1000 iterations of brent's method
PRIME FACTOR 19861
PRIME FACTOR 375563
now trying william's (p+1) method
phase 1 - trying all primes less than 10000
phase 2 - trying last prime less than 1000000
PRIME FACTOR 82798699
PRIME FACTOR 20741975668392230957