1 212 973 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 2⁶⁰

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

P-1

B1 =	26000000
B2 =	136502233140

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	104 / 640

Estimated T-Level: 25.8 ⓘ

Status	Date	User	Residue	Shift
Verified		David Tegerdine	3426C02E238DAE36	0
Verified		Cornelius Caesar	3426C02E238DAE36	0
Verified		Brian J. Beesley	3426C02E238DAE36	0
Verified	2015-11-12	MadPoo	3426C02E238DAE36	633751

Status	Date	User	Residue	Shift	Type	Base
Verified	2025-08-04	kkmrkkblmbrbk	F27A1BF398A36409	588591	1	3
Verified	2025-09-01	Kriesel	F27A1BF398A36409	0	1	3

History

Date	User	Type	Result
2025-09-02	billymac00	CERT	PRP Certification CERT proof power = 6 Proof certified good
2025-09-01	Kriesel	C-PRP	F27A1BF398A36409 PRP proof power = 6 PRP: Verified Proof certified good
2025-08-04	surisuri	CERT	PRP Certification CERT proof power = 6 Proof certified good
2025-08-04	kkmrkkblmbrbk	C-PRP	F27A1BF398A36409 PRP proof power = 6 PRP: Verified Proof certified good
2022-05-06	Sid & Andy	NF-PM1	B1=26000000, B2=136502233140
2018-10-12	Joss	NF-PM1	B1=1212973, B2=133427030, E=12
2018-07-08	ramgeis	NF	no factor from 2^67 to 2^68
2018-07-08	ramgeis	NF	no factor from 2^66 to 2^67
2018-04-26	Joss	NF-PM1	B1=1212973, B2=121297300, E=12
2016-08-27	Bruno Victal	NF-PM1	B1=2500000, B2=62500000, E=12
2016-07-31	Bruno Victal	NF-PM1	B1=2500000, B2=62500000, E=12
2016-02-23	Mark Rose	NF	no factor from 2^58 to 2^60
2015-11-12	MadPoo	C-LL	3426C02E238DAE36
2015-10-13	ramgeis	NF	no factor from 2^65 to 2^66
2015-04-06	monst	NF	no factor from 2^64 to 2^65
2015-03-27	omylist	NF	no factor from 2^63 to 2^64
2013-11-13	David Campeau	NF-PM1	B1=1205000, B2=34945000, E=12
2012-10-11	dbaugh	NF	no factor from 2^62 to 2^63
2011-05-09	megavink	NF	no factor from 2^61 to 2^62
2009-04-13	Sturle Sunde	NF	no factor from 2^60 to 2^61

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