1 621 219 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
887612275731623474111	21	69.6	2011-11-28 20:14:45

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)		Jim Greer	0D4264A18230714E	0
Verified (Factored)	1999-01-29	Henrik Oluf Olsen	0D4264A18230714E	375883

Status	Date	User	Residue	Shift	Type	Base
Verified (Factored)	2025-09-02	Kriesel	08E4BAF12641ECFC	0	1	3

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified	2017-10-02	Oliver Kruse	B228A6DF0062338E	1	0	1	3
Verified	2017-11-01	kkmrkkblmbrbk	B228A6DF0062338E	1	843733	1	3

History

Date	User	Type	Result
2025-09-03	Carlos Pinho	CERT	PRP Certification CERT proof power = 6 Proof certified good
2025-09-02	Kriesel	C-PRP	08E4BAF12641ECFC PRP proof power = 6 PRP: Verified (Factored) Proof certified good
2017-11-01	kkmrkkblmbrbk	C-PRP	M1621219/887612275731623474111 : B228A6DF0062338E PRP: Verified PRP without proof (not generated)
2017-10-02	Oliver Kruse	C-PRP	M1621219/887612275731623474111 : B228A6DF0062338E PRP: Verified PRP without proof (not generated)
2016-03-17	alpertron	NF-PM1	B1=500000, B2=15000000, E=12
2011-11-28	BigBrother	F-PM1	Factor: 887612275731623474111
2010-08-13	GrunwalderGIMP	NF	no factor from 2^1 to 2^63
2010-04-30	Architects Cubed	NF	no factor from 2^60 to 2^61