1 548 541 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
651879015377335014881	21	69.1	2016-02-15 22:05:49

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	107 / 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)		Robert Sartin	E9CC5EC1A06B0BF1	0
Verified (Factored)	1999-02-14	Sauli Siren	E9CC5EC1A06B0BF1	555272
Verified (Factored)	2009-07-18	-Anonymous-	E9CC5EC1A06B0BF1	33049

Status	Date	User	Residue	Shift	Type	Base
Verified (Factored)	2025-09-02	Kriesel	7C588C68A19C7619	0	1	3

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified	2017-10-01	Oliver Kruse	883EE1F56330A81C	1	0	1	3
Verified	2017-10-30	kkmrkkblmbrbk	883EE1F56330A81C	1	499796	1	3

History

Date	User	Type	Result
2025-09-03	Knut Andreas Brungot	CERT	PRP Certification CERT proof power = 6 Proof certified good
2025-09-02	Kriesel	C-PRP	7C588C68A19C7619 PRP proof power = 6 PRP: Verified (Factored) Proof certified good
2017-10-30	kkmrkkblmbrbk	C-PRP	M1548541/651879015377335014881 : 883EE1F56330A81C PRP: Verified PRP without proof (not generated)
2017-10-01	Oliver Kruse	C-PRP	M1548541/651879015377335014881 : 883EE1F56330A81C PRP: Verified PRP without proof (not generated)
2016-02-23	Mark Rose	NF	no factor from 2^62 to 2^63
2016-02-23	Mark Rose	NF	no factor from 2^61 to 2^62
2016-02-23	Mark Rose	NF	no factor from 2^58 to 2^60
2016-02-15	VictordeHollander	F-ECM	Factor: 651879015377335014881 / (ECM curve 21, B1=50000, B2=5000000)
2015-10-11	ramgeis	NF	no factor from 2^65 to 2^66
2015-03-03	VictordeHollander	NF-PM1	B1=10000000, B2=200000000, E=12
2015-02-15	snme2pm1	NF	no factor from 2^64 to 2^65
2015-02-15	snme2pm1	NF	no factor from 2^63 to 2^64
2013-12-05	David Campeau	NF-PM1	B1=945000, B2=27405000, E=12
2011-02-04	James Heinrich	NF-PM1	B1=80000, B2=1360000, E=6
2010-06-02	GrunwalderGIMP	NF	no factor from 2^1 to 2^63
2010-04-28	Architects Cubed	NF	no factor from 2^60 to 2^61
2009-07-18	-Anonymous-	C-LL	E9CC5EC1A06B0BF1