1 548 553 Exponent Status

PrimeNet Exponent Status

M_n

Status

Details

Composite: proven not-prime with both PRP and Lucas-Lehmer tests

No factors below 2⁶⁸

TF target 2⁶¹

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

P-1

B1 =	21200000
B2 =	81672020430

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	106 / 640

Estimated T-Level: 25.8 ⓘ

Status	Date	User	Residue	Shift
Verified		Robert Sartin	BB632FE25A8EC0AD	0
Verified	1998-10-29	Greg Hewgill	BB632FE25A8EC0AD	1174049
Verified	2015-07-20	MadPoo	BB632FE25A8EC0AD	15690

Status	Date	User	Residue	Shift	Type	Base
Verified	2025-09-02	Kriesel	25F6B1C999BB10C3	0	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	25F6B1C999BB10C3 PRP proof power = 6 PRP: Verified Proof certified good
2023-10-10	Sid & Andy	NF-PM1	B1=21200000, B2=81672020430
2023-08-07	Joss	NF-PM1	B1=10001000, B2=17741407320
2023-05-08	Joss	NF-PM1	B1=10001000, B2=8289448440
2023-02-22	Joss	NF-PM1	B1=10001000, B2=3563469000
2022-12-23	Joss	NF-PM1	B1=10001000, B2=1200523170
2018-06-06	ramgeis	NF	no factor from 2^67 to 2^68
2018-02-05	TJAOI	NF	no factor from 2^66 to 2^67
2016-02-23	Mark Rose	NF	no factor from 2^62 to 2^63
2016-02-23	Mark Rose	NF	no factor from 2^58 to 2^60
2016-02-23	Mark Rose	NF	no factor from 2^61 to 2^62
2015-10-11	ramgeis	NF	no factor from 2^65 to 2^66
2015-07-20	MadPoo	C-LL	BB632FE25A8EC0AD
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
2010-06-06	GrunwalderGIMP	NF	no factor from 2^1 to 2^63
2010-04-28	Architects Cubed	NF	no factor from 2^60 to 2^61

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