425 521 Exponent Status

PrimeNet Exponent Status

M_n

Status

Details

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

Factored

Factor	Digits	Bits	Date
43941552787919389013204157573551	32	105.1	2025-08-06 21:27:08

ECM

Estimated T-Level: 30.7 ⓘ

TF below 2^97 is very unlikely to find new factors due to ECM effort.

Status	Date	User	Residue	Shift
Verified (Factored)		David Slowinski	22C6	0
Verified (Factored)		David Brlej	F6F4BD66355C22C6	0
Verified (Factored)		Lance Optican	F6F4BD66355C22C6	0
Verified (Factored)		Eivind Triel	F6F4BD66355C22C6	266138
Verified (Factored)	2016-06-01	MadPoo	F6F4BD66355C22C6	243114

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified	2025-08-06	Ismo Laitela	25F247F58EB12CCB	1	400377	5	3

History

Date	User	Type	Result
2025-08-08	Oliver Kruse	CERT	PRP Certification Proof certified good
2025-08-06	Ismo Laitela	C-PRP	M425521/43941552787919389013204157573551 : 25F247F58EB12CCB PRP proof power = 6 PRP: Verified Proof certified good
2025-08-06	Ismo Laitela	F-ECM	Factor: 43941552787919389013204157573551 / (ECM curve 7, B1=500000, B2=4060028115, Edwards Sigma=8755290266585952)
2023-10-13	masser	NF-PM1	B1=80000000, B2=1720512333540
2023-01-17	masser	NF-PP1	Start=2/7, B1=20000000, B2=640000000
2023-01-15	masser	NF-PP1	Start=6/5, B1=20000000, B2=640000000
2023-01-07	masser	NF-PP1	Start=149/13, B1=20000000, B2=620000000
2022-02-16	lycorn	NF-PM1	B1=20000000, B2=504127333710
2022-02-06	LordJulius	NF	no factor from 2^67 to 2^68
2022-02-06	LordJulius	NF	no factor from 2^66 to 2^67
2018-12-09	Gordon Spence	NF	no factor from 2^65 to 2^66
2018-01-07	BloodERazor	NF	no factor from 2^64 to 2^65
2016-06-01	MadPoo	C-LL	F6F4BD66355C22C6
2016-02-23	Mark Rose	NF	no factor from 2^58 to 2^60
2015-11-15	Gordon Spence	NF	no factor from 2^63 to 2^64
2015-11-15	Gordon Spence	NF	no factor from 2^62 to 2^63
2015-07-15	NR	NF	no factor from 2^61 to 2^62
2012-08-27	markr	NF-PM1	B1=10000000, B2=400000000, E=12
2012-04-21	Sid & Andy	NF	no factor from 2^60 to 2^61
2012-03-10	Joss	NF-PM1	B1=1257421
2011-08-06	Joss	NF-PM1	B1=1005937
2010-07-30	Rob_Dee	NF-PM1	B1=1000000, B2=2000000, E=6
2010-07-29	Rob_Dee	NF-PM1	B1=500000, B2=1000000

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