Marin Mersenne 2^P-1
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Great Internet Mersenne Prime Search
GIMPS
Finding World Record Primes Since 1996

PrimeNet Exponent Status

Exponent Range:





MnDetails
8221
Composite, with 6 known prime factors. Cofactor is composite.
Trial Factored to 268
TF target 244
Factored
FactorDigitsBitsDate
920753619.8old
9667897723.2old
18480809824.1old
664135739274326471755.9old
504351329908140879449460961432995.3old
22267154382986616180773050643701006785708742137.42025-01-19 06:59:05
ECM
DigitsB1Curves
2550000280 / 280
30250000640 / 640
3510000001566 / 1566
4030000004588 / 4588
45110000009201 / 9201
50440000006591 / 16550
Estimated T-Level: 47.0 ⓘ
TF below 2^151 is very unlikely to find new factors due to ECM effort.
PRP Cofactor
StatusProofDateUserResidueNumber of
known factors		ShiftTypeBase
Factored
No proof (small exponent)
2017-09-21Oliver KruseE3FBBDFA850BC99D5013
Factored
No proof (small exponent)
2017-10-02kkmrkkblmbrbkE3FBBDFA850BC99D5013
Factored
No proof (small exponent)
2017-12-07ATHE3FBBDFA850BC99D548113
Factored
No proof (small exponent)
2020-04-17Oliver Kruse859897F075C263F25738053
Factored
No proof (small exponent)
2024-07-01kkmrkkblmbrbk859897F075C263F25653653
Verified
No proof (small exponent)
2025-01-19nordi859897F075C263F26482753
History
DateUserTypeResult
2025-05-20masserNF-PP1Start=126/71, B1=1300000000, B2=1298700000000
2025-01-19nordiC-PRPM8221/920753/9667897/18480809/66413573927432647/50435132990814087944946096143/222671543829866161807730506437010067857087 : 859897F075C263F2
2025-01-19nordiF-ECMFactor: 222671543829866161807730506437010067857087 / ECM curve 309, B1=110000000, B2=3103899523725, Edwards Sigma=750835391591304
2024-07-01kkmrkkblmbrbkC-PRPM8221/18480809/50435132990814087944946096143/66413573927432647/920753/9667897 : 859897F075C263F2
2023-09-01JacobZNF-PM1B1=72000000000, B2=265422648792401100
2021-08-27Seth_TrNF-PM1B1=400000000
2021-08-25H MichaelsonNF-PM1B1=10000000, B2=1000000000
2020-04-17Oliver KruseC-PRPM8221/920753/9667897/18480809/66413573927432647/50435132990814087944946096143 : 859897F075C263F2
2017-12-07ATHC-PRPM8221/920753/9667897/18480809/66413573927432647/50435132990814087944946096143 : E3FBBDFA850BC99D
2017-10-02kkmrkkblmbrbkC-PRPM8221/920753/9667897/18480809/66413573927432647/50435132990814087944946096143 : E3FBBDFA850BC99D
2017-09-21Oliver KruseC-PRPM8221/known_factors : E3FBBDFA850BC99D