YAFU factors a 100 digit number for me…

On Friday, I left YAFU factoring a 100 digit number. I returned to find that it had discovered:

57790 93002 97410 10009 81807 59480 96292 62385 64081 79034 01512 68667
60949 55202 41611 02063 00992 86747 29621 36069 = 
85404 41503 10330 70274 85067 33621 20528 36393 71759 33321 * 
67667 37996 94567 83271 38746 19751 00109 79749 75402 10589

It took about 7.6 hours of compute time.

Addendum: I was reading “Factoring by electronic mail”, a 1990 paper by Lenstra and Manasse, and they listed some times for factorization of some large numbers. In Table 4, they list a bunch of challenging numbers, including the 93 digit composite factor of 7139+1. Their system took 13 days. YAFU was able to factor it in about 70 minutes on my current desktop machine:

Total factoring time = 4283.6700 seconds


***factors found***

P1 = 2
P1 = 2
P1 = 2
P3 = 557
PRP22 = 5312442648966139012589
PRP57 = 651666519182971782190402264651775450396158503528225547931
PRP36 = 190705279598948669274660288301207361

It found the small primes via trial division, the 22 digit prime factor via the ECM method, and then churned the rest out using the quadratic sieve.

One thought on “YAFU factors a 100 digit number for me…”

  1. Ben Buhrow

    Hello, I just stumbled across this post. Congrats on the large factorization with YAFU, I’m glad it worked for you. Out of curiousity, what kinds of numbers are you interested in factoring and how did you discover YAFU?

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