991 Exponent Status

Great Internet Mersenne Prime Search
GIMPS
Finding World Record Primes Since 1996

PrimeNet Exponent Status

M_n

Details

Composite, with 4 known prime factors. Cofactor is PRP (Probable-Prime).

Trial Factored to 2⁶⁸

TF target 2⁴⁴

Factored

Factor	Digits	Bits	Date
8218291649	10	32.9	old
41473350001	11	35.3	old
231620367206687	15	47.7	old
6721885469050382920298612421830968178768028093133627640714502537112053019071272802490029644416444090606146146238871876925423959	127	421.3	2015-06-18 01:32:00

Status	Proof	Date	User	Residue	Number of known factors	Shift	Type	Base
Factored	No proof (small exponent)	2024-09-06	George Woltman	PRP_PRP_PRP_PRP_	4	0	1	3

History

Date	User	Type	Result
2024-09-06	George Woltman	P-PRP	M991/8218291649/41473350001/231620367206687/6721885469050382920298612421830968178768028093133627640714502537112053019071272802490029644416444090606146146238871876925423959 PRP Cofactor
2015-06-18	-anonymous-	F-ECM	Factor: 6721885469050382920298612421830968178768028093133627640714502537112053019071272802490029644416444090606146146238871876925423959
2009-05-17	-anonymous-	F	Factor: 340840085969272441649
2004-02-07	Will Edgington	NF-PM1	B1=4290000000
2003-12-02	Will Edgington	NF-PM1	B1=4290000000
2001-04-01	crash893	F	Factor: 340840085969272441649
2000-08-01	-anonymous-	F	Factor: 340840085969272441649