Marin Mersenne 2^P-1
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Finding World Record Primes Since 1996

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MnStatusDetails
1947851Composite, with 1 known prime factor. Cofactor is composite.
Factored
FactorDigitsBitsDate
20850710389976593511960.92009-08-13 00:12:57
ECM
DigitsB1Curves
2550000280 / 280
30250000106 / 640
Estimated T-Level: 25.8 ⓘ
TF below 2^81 is very unlikely to find new factors due to ECM effort.
LL
StatusDateUserResidueShift
Verified (Factored)Mischa KennFEC26F2B854440460
Verified (Factored)1998-12-27Troy HolmFEC26F2B85444046829266
PRP
StatusDateUserResidueShiftTypeBase
Verified (Factored)2025-09-02Kriesel97BAA8D002445091013
PRP Cofactor
StatusDateUserResidueNumber of
known factors		ShiftTypeBase
Verified2017-10-05Oliver KruseB06F467342269C8D1013
Verified2017-11-11kkmrkkblmbrbkB06F467342269C8D179762313
History
DateUserTypeResult
2025-09-03ANONYMOUSCERT
PRP Certification
CERT proof power = 6
Proof certified good
2025-09-02KrieselC-PRP
97BAA8D002445091
PRP proof power = 6
PRP: Verified (Factored)
Proof certified good
2017-11-11kkmrkkblmbrbkC-PRP
M1947851/2085071038997659351 : B06F467342269C8D
PRP: Verified
PRP without proof (not generated)
2017-10-05Oliver KruseC-PRP
M1947851/2085071038997659351 : B06F467342269C8D
PRP: Verified
PRP without proof (not generated)
2016-03-17alpertronNF-PM1
B1=500000, B2=15000000, E=12
2009-08-13SubPrimeF-ECM
Factor: 2085071038997659351