1 225 687 Exponent Status

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

PrimeNet Exponent Status

M_n

Status

Details

Composite, with 1 known prime factor. Cofactor is composite.

Factored

Factor	Digits	Bits	Date
3897657490557025003337	22	71.7	2013-10-07 20:35:52

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	100 / 640

Estimated T-Level: 25.8 ⓘ

TF below 2^81 is very unlikely to find new factors due to ECM effort.

Status	Date	User	Residue	Shift
Verified (Factored)		David Slowinski	0E3	0
Verified (Factored)		Joel Armengaud	DABCF316230840E3	0
Verified (Factored)	2002-08-10	S57483	DABCF316230840E3	1105711

Status	Date	User	Residue	Shift	Type	Base
Verified (Factored)	2025-09-01	Kriesel	202FB327C4C7D135	0	1	3

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified	2017-09-29	Oliver Kruse	5E31606390C80078	1	0	1	3
Verified	2017-10-19	kkmrkkblmbrbk	5E31606390C80078	1	705933	1	3

History

Date	User	Type	Result
2025-09-02	Dave Scott	CERT	PRP Certification CERT proof power = 6 Proof certified good
2025-09-01	Kriesel	C-PRP	202FB327C4C7D135 PRP proof power = 6 PRP: Verified (Factored) Proof certified good
2022-03-07	LordJulius	NF	no factor from 2^58 to 2^60
2017-10-19	kkmrkkblmbrbk	C-PRP	M1225687/3897657490557025003337 : 5E31606390C80078 PRP: Verified PRP without proof (not generated)
2017-09-29	Oliver Kruse	C-PRP	M1225687/3897657490557025003337 : 5E31606390C80078 PRP: Verified PRP without proof (not generated)
2016-03-17	alpertron	NF-PM1	B1=300000, B2=10000000, E=12
2013-10-07	David Campeau	F-ECM	Factor: 3897657490557025003337
2012-10-18	dbaugh	NF	no factor from 2^62 to 2^63
2012-09-13	Axelsson	NF	no factor from 2^61 to 2^62
2009-02-17	Sturle Sunde	NF	no factor from 2^60 to 2^61