1 978 439 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
43571439855436520959	20	65.2	2011-02-15 17:45:04

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	106 / 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)		Robin Bussell	488E2417DAEC5DE4	0
Verified (Factored)	1999-01-17	Justin Santamaria	488E2417DAEC5DE4	1729911

Status	Date	User	Residue	Shift	Type	Base
Verified (Factored)	2025-09-02	Kriesel	1498B13D09E11F4F	0	1	3

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified	2017-10-05	Oliver Kruse	08E426B95EBD1F37	1	0	1	3
Verified	2017-11-12	kkmrkkblmbrbk	08E426B95EBD1F37	1	1815620	1	3

History

Date	User	Type	Result
2025-09-03	Chun sung soo	CERT	PRP Certification CERT proof power = 6 Proof certified good
2025-09-02	Kriesel	C-PRP	1498B13D09E11F4F PRP proof power = 6 PRP: Verified (Factored) Proof certified good
2023-06-03	USAFSS	NF-PM1	B1=750000, B2=813466038
2022-08-13	USAFSS	NF-PM1	B1=88000, B2=95986800
2022-03-09	LordJulius	NF	no factor from 2^1 to 2^60
2017-11-12	kkmrkkblmbrbk	C-PRP	M1978439/43571439855436520959 : 08E426B95EBD1F37 PRP: Verified PRP without proof (not generated)
2017-10-05	Oliver Kruse	C-PRP	M1978439/43571439855436520959 : 08E426B95EBD1F37 PRP: Verified PRP without proof (not generated)
2011-02-15	kurly	F-PM1	Factor: 43571439855436520959
2009-12-22	S485122	NF	no factor from 2^60 to 2^61