28 807 Exponent Status

PrimeNet Exponent Status

M_n

Status

Details

Composite, with 1 known prime factor. Cofactor is composite.

Factored

Factor	Digits	Bits	Date
6857518945523406873133566668158750818324839	43	142.3	2023-07-27 10:21:31

ECM

Estimated T-Level: 42.8 ⓘ

TF below 2^137 is very unlikely to find new factors due to ECM effort.

Status	Date	User	Residue	Shift
Verified (Factored)		Unknown	13B4	0
Verified (Factored)		George Woltman	DBBE6240726A93B4	0
Verified (Factored)		Brian J. Beesley	DBBE6240726A93B4	0
Verified (Factored)	2015-04-11	MadPoo	DBBE6240726A93B4	10243

Status	Date	User	Residue	Number of known factors	Shift	Type	Base
Verified	2023-07-27	masser	39ECD250F4AFCB7C	1	3707	5	3
Verified	2023-07-30	Naegi Makoto	39ECD250F4AFCB7C	1	3334	5	3

P-1 factors

Date	Factor	B1	B2
2023-07-27	6857518945523406873133566668158750818324839	8000000000	2253172624873170

History

Date	User	Type	Result
2023-07-30	Naegi Makoto	C-PRP	M28807/6857518945523406873133566668158750818324839 : 39ECD250F4AFCB7C PRP: Verified PRP without proof (small exponent)
2023-07-27	masser	C-PRP	M28807/6857518945523406873133566668158750818324839 : 39ECD250F4AFCB7C PRP: Verified PRP without proof (small exponent)
2023-07-27	masser	F-PM1	Factor: 6857518945523406873133566668158750818324839 / (P-1, B1=8000000000, B2=2253172624873170)
2023-07-07	masser	NF-PP1	Start=91/37, B1=250000000, B2=10000000000
2021-05-07	ATH	NF-PP1	Start=2/7, B1=500000000, B2=101500000000
2020-05-24	Yxinity	NF	no factor from 2^65 to 2^66
2020-05-24	Yxinity	NF	no factor from 2^65 to 2^66
2019-07-21	Yxinity	NF	no factor from 2^64 to 2^65
2019-07-20	Yxinity	NF	no factor from 2^64 to 2^65
2018-04-10	Yxinity	NF	no factor from 2^63 to 2^64
2018-04-09	Yxinity	NF	no factor from 2^63 to 2^64
2017-05-30	mikr	NF-PM1	B1=12000000000, B2=960000000000, E=12
2016-09-20	Sid & Andy	NF	no factor from 2^62 to 2^63
2016-02-23	LaurV	NF	no factor from 2^57 to 2^58
2015-04-11	MadPoo	C-LL	DBBE6240726A93B4
2013-11-07	David Campeau	NF-PM1	B1=204545000, B2=10636340000, E=12
2012-04-02	bcp19	NF	no factor from 2^61 to 2^62
2012-04-02	bcp19	NF	no factor from 2^60 to 2^61
2009-02-07	Sturle Sunde	NF	no factor from 2^59 to 2^60
2009-01-14	Sturle Sunde	NF	no factor from 2^58 to 2^59

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