2 181 581 Exponent Status

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

PrimeNet Exponent Status

M_n

Status

Details

Composite, with 2 known prime factors. Cofactor is composite.

Factored

Factor	Digits	Bits	Date
10837595003282993167	20	63.2	2008-12-22 09:53:06
5551395448455411273940927	25	82.2	2025-02-24 11:33:05

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	167 / 640

Estimated T-Level: 26.3 ⓘ

TF below 2^82 is very unlikely to find new factors due to ECM effort.

Status	Date	User	Residue	Shift
Verified (Factored)		Ethan Hansen	A2FAB7285AABB09C	0
Verified (Factored)	1999-02-07	Stephen Wood	A2FAB7285AABB09C	899772

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified (Factored)	2017-10-10	kkmrkkblmbrbk	5865CD68FA09E896	1	0	1	3
Verified (Factored)	2017-10-24	Oliver Kruse	5865CD68FA09E896	1	1108507	1	3
Verified	2025-03-01	ATH	91F4639573D15A21	2	1638682	5	3

History

Date	User	Type	Result
2025-03-01	Jonathan Webb	CERT	PRP Certification Proof certified good
2025-03-01	ATH	C-PRP	M2181581/10837595003282993167/5551395448455411273940927 : 91F4639573D15A21 PRP proof power = 7 PRP: Verified Proof certified good
2025-02-24	TJAOI	F-ECM	Factor: 5551395448455411273940927 / (ECM curve 11, B1=250000, B2=254050335, Edwards Sigma=5425841953826430)
2017-10-24	Oliver Kruse	C-PRP	M2181581/10837595003282993167 : 5865CD68FA09E896 PRP: Verified (Factored) PRP without proof (not generated)
2017-10-10	kkmrkkblmbrbk	C-PRP	M2181581/10837595003282993167 : 5865CD68FA09E896 PRP: Verified (Factored) PRP without proof (not generated)
2016-03-22	alpertron	NF-PM1	B1=500000, B2=15000000, E=12
2008-12-22	Never Odd Or Even	F-ECM	Factor: 10837595003282993167