is 2 6991531 - 1
has 2104661 decimal digits
takes 1.525 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L879428CDDDB41F5Cdouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual272136.784668.0556%20000002586265505.05316.9843%141.837770.2867%2.2311%
PrimeNet2630.228363.4921%300008000000.02273.3129%0.251064.7015%1.2095%
GPU722674.250065.6716%450009000000.02902.2401%4.278966.4406%0.7690%
Difference+5+132.5346+2.3839%+1955000+257726550+5.0242+4.7442%+137.5587+3.8460%+1.4621%

Known prime factors:
No known factors for M6991531

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2001-11-03T00:00:00ANONYMOUSv4_computers2500087500---0.009--0.432%
2011-07-02T17:17:00Carsten Kossendeyleela44500013572500---0.367--3.529%
2021-11-08T18:35:26Seth_TrManual testing30000007500000012---2.189--5.988%
2021-12-06T07:06:17Seth_TrManual testing2000000258626550---5.053--6.984%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-07-29T00:00:00ANONYMOUSv4_computers21261--0.044--
1998-08-09T00:00:00ANONYMOUSv4_computers21262--0.088--
2005-09-03T00:00:00ANONYMOUSv4_computers21263--0.228--
2014-01-17T20:40:00lycornManual testing263264--0.281--
2014-01-18T00:05:00lycornManual testing264265--0.534--
2015-07-03T01:16:00VictordeHollanderManual testing265266--1.069--
2016-04-28T01:09:01Gordon SpenceManual testing266267--2.138--
2018-02-27T00:22:06-Anonymous-Manual testing267268--4.275--
2020-04-03T12:20:56TJAOIManual testing268269--8.551--
2020-07-26T22:52:14takahashiManual testing269270--17.10--
2020-09-15T23:43:47takahashiManual testing270271--34.20--
2021-10-13T15:11:10SRBaseManual testing271272--68.40--


ECM factoring results:
Total ECM effort:1.989 GHz-days
Estimated T-Level:1.154
DigitsB1CompleteFacMiss
20110000.23179.392%
25500000.02197.887%
302500000.00199.865%


ECM Summary

B1B2factorcurvesGHz-days
50000500000061.989


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-10-21T00:00:00ANONYMOUSv4_computers879428CDDDB41F5C1.525
2001-12-22T00:00:00ANONYMOUSv4_computers879428CDDDB41F5C1.525


PRP results:
No PRP results for M6991531


P-1 factor-bounds graph:
B1 = 2000000, B2 = 258626550 (P-1 stage 2)
B1 = 3000000, B2 = 75000000 (P-1 stage 2)
B1 = 3000000 (P-1 stage 1)
B1 = 2000000 (P-1 stage 1)
B1 = 445000, B2 = 13572500 (P-1 stage 2)
B1 = 445000 (P-1 stage 1)
B1 = 25000, B2 = 87500 (P-1 stage 2)
B1 = 25000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2021-12-06T07:06:17+00:00