196 171 Exponent Status

Great Internet Mersenne Prime Search
GIMPS
Finding World Record Primes Since 1996

PrimeNet Exponent Status

M_n

Status

Details

Factored

Factor	Digits	Bits	Date
12261356998027304647511981511886312561	38	123.2	2020-11-14 17:19:51

ECM

Digits	B1	Curves
25	50000	280 / 280
30	250000	640 / 640
35	1000000	404 / 1566

Estimated T-Level: 31.3 ⓘ

TF below 2^99 is very unlikely to find new factors due to ECM effort.

Status	Date	User	Residue	Shift
Verified (Factored)		Amdahl 6 - 1989	107ADE86	0
Verified (Factored)		Martin Eibl	BCB5F112107ADE86	0
Verified (Factored)		Brian J. Beesley	BCB5F112107ADE86	0
Verified (Factored)		Eivind Triel	BCB5F112107ADE86	55607
Verified (Factored)	2016-06-01	MadPoo	BCB5F112107ADE86	49789

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified	2020-11-16	arnaud	CB275CF12CBB7500	1	21457	5	3
Verified	2023-08-24	USAFSS	CB275CF12CBB7500	1	123382	5	3

History

Date	User	Type	Result
2023-08-24	curtisc	CERT	PRP Certification Proof certified good
2023-08-24	USAFSS	C-PRP	M196171/12261356998027304647511981511886312561 : CB275CF12CBB7500 PRP proof power = 5 PRP: Verified Proof certified good
2022-03-07	LordJulius	NF	no factor from 2^54 to 2^55
2020-11-16	Ben Delo	CERT	PRP Certification Proof certified good
2020-11-16	arnaud	C-PRP	M196171/12261356998027304647511981511886312561 : CB275CF12CBB7500 PRP proof power = 5 PRP: Verified Proof certified good
2020-11-14	nordi	F-ECM	Factor: 12261356998027304647511981511886312561 / (ECM curve 116, B1=1000000, B2=100000000, Sigma=1065100692655692)
2019-12-12	Gordon Spence	NF	no factor from 2^65 to 2^66
2018-01-01	BloodERazor	NF	no factor from 2^64 to 2^65
2016-06-01	MadPoo	C-LL	BCB5F112107ADE86
2016-02-23	Mark Rose	NF	no factor from 2^57 to 2^58
2015-12-07	Gordon Spence	NF	no factor from 2^63 to 2^64
2015-12-07	Gordon Spence	NF	no factor from 2^62 to 2^63
2015-08-25	NR	NF	no factor from 2^61 to 2^62
2013-10-10	alpertron	NF-PM1	B1=100000000, B2=2000000000, E=12
2013-08-12	lycorn	NF	no factor from 2^60 to 2^61
2009-02-04	axn	NF-PM1	B1=5000000, B2=200000000, E=12
2009-01-27	Sturle Sunde	NF	no factor from 2^59 to 2^60
2008-12-31	Sturle Sunde	NF	no factor from 2^58 to 2^59