is 2 261251 - 1
has 78645 decimal digits
takes 0.002 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L-unknown--unknown-
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual267113.737073.1343%30000000100358126969105,417.947323.4633%5,531.684379.4379%
Target2440.000059.0909%50001200000.000110.5596%0.000163.4107%
Difference+23+113.7370+14.0434%+29995000+10035812576910+5,417.9472+12.9037%+5,531.6842+16.0271%

Known prime factors (2 factors, 183.4 bits, 0.07021923% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
261251319844336623280871754.82861213992793
61213992793
2014-04-231612139927930.018333.04561.720
26125152304915432475248799982840500929814476939128.6201001047181302181595476818088752384
28 × 7 × 997 × 90481 × 200467 × 585313 × 52775569741
2022-05-03585313527755697416.895e+1128.49553.211

1 Composite Factors:
P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2021-09-15Oliver KruseOllaptop30000000300000000024---1.901--12.609%
2022-05-03Oliver KruseThreadripper-PC300000001003581269691039128.6205,4180.00410,83623.463%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2001-02-18ANONYMOUSv4_computers??54.828170.0090.0040.019
2003-08-25ANONYMOUSv4_computers??54.828170.0090.0040.019
1999-11-24ANONYMOUSv4_computers252253--0.002--
2000-04-27ANONYMOUSv4_computers21254--0.009--


ECM factoring results:
Total ECM effort:13.393 GHz-days
Estimated T-Level:27.691
DigitsB1CompleteFacMiss
201100038.6170.000%
25500005.2910.504%
302500000.53858.375%
3510000000.04395.764%
4030000000.00399.715%


ECM Summary

B1B2factorcurvesGHz-days
5000050000002812.049
250000250000001977.182
2500003125000070.276
2500003425000070.287
2500003630725270.294
2500003650000070.294
2500003671866680.337
25000036750000421.771
25000038500000210.903


Lucas-Lehmer results:
No L-L results for M261251


PRP results:
dateuseridcompidcofactorsres64PRP
2017-09-22Oliver KruseOllaptop
31984433662328087
2AD8A87784A797__no
2017-09-22Oliver KruseManual testing
31984433662328087
2AD8A87784A797__no
2017-10-12Oliver KruseGTX-12AD8A87784A797__no
2017-11-06kkmrkkblmbrbkc4.xlarge
31984433662328087
2AD8A87784A797__no
2020-04-17Oliver KruseAddPrpType5
31984433662328087
EDD9D2C3B5C5B7__no
2022-05-03LordJuliusWhiteBox
31984433662328087
523049154324752487999828405009298144769
EDD9D2C3B5C5B704no
2022-05-04Oliver KruseServer-Phi
31984433662328087
523049154324752487999828405009298144769
EDD9D2C3B5C5B704no


P-1 factor-bounds graph:
B1 = 30000000, B2 = 10035812696910 (P-1 stage 2)
B1 = 30000000, B2 = 3000000000 (P-1 stage 2)
B1 = 30000000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2023-02-04T05:27:04+00:00