1 778 731 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 =	20000000
B2 =	340095305550

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	105 / 640

Estimated T-Level: 25.8 ⓘ

Status	Date	User	Residue	Shift
Verified		John Lloyd	CEAB7E20AFA7B31E	0
Verified	1998-12-13	Roger Smith	CEAB7E20AFA7B31E	1310269
Verified	2015-07-04	MadPoo	CEAB7E20AFA7B31E	658205

Status	Date	User	Residue	Shift	Type	Base
Verified	2025-09-02	Kriesel	50C5D48D6B689132	0	1	3

History

Date	User	Type	Result
2025-09-03	LookAS	CERT	PRP Certification CERT proof power = 6 Proof certified good
2025-09-02	Kriesel	C-PRP	50C5D48D6B689132 PRP proof power = 6 PRP: Verified Proof certified good
2023-08-07	linament	NF-PM1	B1=20000000, B2=340095305550
2023-08-06	linament	NF-PM1	B1=20000000
2023-05-13	Joss	NF-PM1	B1=1778731, B2=6151578510
2023-02-27	Joss	NF-PM1	B1=1778731, B2=2661445710
2023-01-07	Joss	NF-PM1	B1=1778731, B2=916395480
2022-08-04	masser	NF-PP1	Start=137/37, B1=1600000, B2=57600000
2019-06-17	TJAOI	NF	no factor from 2^67 to 2^68
2018-10-19	Joss	NF-PM1	B1=1778731, B2=195660410, E=12
2018-07-04	Joss	NF-PM1	B1=1778731, B2=177873100, E=12
2018-04-09	TJAOI	NF	no factor from 2^66 to 2^67
2016-02-23	Mark Rose	NF	no factor from 2^61 to 2^62
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
2015-09-11	ramgeis	NF	no factor from 2^65 to 2^66
2015-07-04	MadPoo	C-LL	CEAB7E20AFA7B31E
2015-05-25	mikr	NF-PM1	B1=2475400, B2=86660000, E=12
2015-05-08	snme2pm1	NF	no factor from 2^64 to 2^65
2015-05-08	snme2pm1	NF	no factor from 2^63 to 2^64
2014-09-19	Joss	NF-PM1	B1=172168
2014-05-09	Joss	NF-PM1	B1=136084
2014-04-10	-Anonymous-	NF-PM1	B1=100000
2011-02-10	Carsten Kossendey	NF-PM1	B1=95000, B2=1615000, E=6
2010-10-04	GrunwalderGIMP	NF	no factor from 2^1 to 2^63
2010-04-21	Architects Cubed	NF	no factor from 2^60 to 2^61

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