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:










MnStatusDetails
1291Composite, with 2 known prime factors. Cofactor is composite.
Factored
FactorDigitsBitsDate
9989430808971239.9old
840514004229533021895445818412996.1old
ECM
DigitsB1Curves
2550000280 / 280
30250000640 / 640
3510000001566 / 1566
4030000004588 / 4588
45110000009201 / 9201
504400000016550 / 16550
5511000000040830 / 40830
60260000000105362 / 105362
6580000000077271 / 194238
Estimated T-Level: 62.0 ⓘ
TF below 2^201 is very unlikely to find new factors due to ECM effort.
PRP Cofactor
StatusDateUserResidueNumber of
known factors		ShiftTypeBase
Verified2017-09-27Oliver Kruse765D62F0248EC4702013
Verified2017-10-09Chang Chia-Tche765D62F0248EC4702013
Verified2017-10-12kkmrkkblmbrbk765D62F0248EC470243713
Verified2020-04-17Oliver Kruse91467BA1E6089CC2247653
Verified2020-08-12_p95holder_91467BA1E6089CC2217653
History
DateUserTypeResult
2021-07-19ViliamFNF-PP1
Start=2/7, B1=1000000000, B2=221000000000
2021-03-27nordiNF-PM1
B1=1000000000000, B2=2232843418649129478
2020-08-12_p95holder_C-PRP
M1291/998943080897/84051400422953302189544581841 : 91467BA1E6089CC2
PRP: Verified
PRP without proof (small exponent)
2020-04-17Oliver KruseC-PRP
M1291/998943080897/84051400422953302189544581841 : 91467BA1E6089CC2
PRP: Verified
PRP without proof (small exponent)
2017-10-12kkmrkkblmbrbkC-PRP
M1291/998943080897/84051400422953302189544581841 : 765D62F0248EC470
PRP: Verified
PRP without proof (not generated)
2017-10-09Chang Chia-TcheC-PRP
M1291/known_factors : 765D62F0248EC470
PRP: Verified
PRP without proof (not generated)
2017-09-27Oliver KruseC-PRP
M1291/998943080897/84051400422953302189544581841 : 765D62F0248EC470
PRP: Verified
PRP without proof (not generated)
2017-09-25csabaC-PRP
M1291/known_factors : 765D62F0248EC470
PRP without proof (not generated)
2016-09-07kkmrkkblmbrbkNF-PM1
B1=1000000000, B2=100000000000, E=12