2 851 Exponent Status

PrimeNet Exponent Status

M_n

Details

Composite: proven not-prime with Lucas-Lehmer test

No factors below 2⁶⁶

TF target 2⁴⁴

P-1

B1 =	6000000000000
B2 =	9223372036854775807

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	640 / 640
35	1000000	1566 / 1566
40	3000000	4588 / 4588
45	11000000	9201 / 9201
50	44000000	16550 / 16550
55	110000000	40830 / 40830
60	260000000	105362 / 105362
65	800000000	194238 / 194238
70	2400000000	157319 / 350860

Estimated T-Level: 67.2 ⓘ

TF below 2^218 is very unlikely to find new factors due to ECM effort.

Status	Date	User	Residue	Shift	Software
Verified		Unknown	66DD	0	Unknown,(aka U)
Verified		George Woltman	7982D1CA51BEE6DD	0	Woltman,Prime95,first web release,(aka W4)
Verified		Brian J. Beesley	7982D1CA51BEE6DD	0	Mac,John Sweeney,v1.4,(aka J3)
Verified	2015-04-11	MadPoo 🙂	7982D1CA51BEE6DD	2773	Windows 64-bit,Prime95,v26,(aka We4)

History

Date	User	Type	Result
2025-12-15	One Man	NF-PM1	B1=462941043406, B2=751279885199633790
2024-10-20	-anonymous-	NF-PM1	B1=6000000000000, B2=1.4003059100843E+19
2023-08-11	masser	NF-PP1	Start=6/5, B1=3390000000, B2=606810000000
2023-08-10	masser	NF-PP1	Start=2/7, B1=3390000000, B2=606810000000
2023-07-16	masser	NF-PP1	Start=90/23, B1=3390000000, B2=135600000000
2023-07-06	masser	NF-PM1	B1=216000000000, B2=407260548568773900
2023-02-09	Joss	NF-PM1	B1=63000000000, B2=100103983685375670
2023-02-08	Joss	NF-PM1	B1=63000000000, B2=6479091987117750
2023-02-08	Joss	NF-PM1	B1=63000000000, B2=186371985249450
2022-07-11	Anton Repko	NF	no factor TF: 65-66
2021-08-17	H Michaelson	NF-PP1	Start=2/7, B1=1000000, B2=100000000
2021-01-13	Anton Repko	NF	no factor TF: 64-65
2018-03-18	snme2pm1	NF	no factor TF: 63-64
2016-10-09	snme2pm1	NF	no factor TF: 62-63
2016-02-23	LaurV	NF	no factor TF: 57-58
2015-07-18	snme2pm1	NF	no factor TF: 61-62
2015-04-11	MadPoo 🙂	C-LL	7982D1CA51BEE6DD
2014-10-01	James Hintz	NF-PM1	B1=100000000000, B2=10000000000000, E=12
2013-11-15	David Campeau	NF-PM1	B1=11788975000
2012-08-02	bcp19	NF	no factor TF: 60-61
2011-04-17	Joss	NF-PM1	B1=10000000000
2011-01-10	monst	NF	no factor TF: 58-60
2003-02-16	Alex Kruppa	NF	no factor TF: 1-57
2003-01-25	Alex Kruppa	NF	no factor TF: 1-57
2003-01-16	Alex Kruppa	NF	no factor TF: 1-57
2002-12-31	-anonymous-	NF-PM1	B1=4290000000
2002-09-14	-anonymous-	NF-PM1	B1=3221225472, B2=4290000000, E=48
2002-08-03	-anonymous-	NF-PM1	B1=2147483648, B2=4290000000, E=48
2002-06-02	-anonymous-	NF-PM1	B1=1073741824, B2=4290000000
2001-06-03	-anonymous-	NF-PM1	B1=43000000, B2=4290000000
2001-06-03	-anonymous-	NF-PM1	B1=3000000000, B2=4290000000
2001-02-11	-anonymous-	NF-PM1	B1=1000000, B2=100000000
2000-08-10	-anonymous-	NF	no factor TF: 1-56
2000-02-01	-anonymous-	NF	no factor TF: 54-55
1999-12-23	-anonymous-	NF	no factor TF: 53-54
1999-09-22	-anonymous-	NF	no factor TF: 52-53
1998-07-05	-anonymous-	NF	no factor TF: 50-52

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