is 2 31531 - 1
has 9492 decimal digits
takes 0.000 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
-unknown- primality tests remaining
ResidueStatus
L-L-unknown--unknown-
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actualunknown20000000050000000000.368648.9156%0.368648.9156%48.9156%
PrimeNet2400.000062.5000%500100000.00004.1558%0.000064.0584%1.5584%
GPU722440.000165.9091%500100000.00001.7845%0.000166.5174%0.6083%
Difference-44-0.0001-65.9091%+199999500+4999990000+0.3686+47.1311%+0.3685-17.6018%-17.6018%

Known prime factors (2 factors, 135.3 bits, 0.42897412% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
31531432857569928.6896864
24 × 3 × 11 × 13
-16161.685e-91.278e-82.601e-8
3153112048156165165036950991450793513733106.5711910525540763857307251823728
24 × 67 × 12621901 × 141199543647214049
2017-07-20126219011411995436472140494.895e+126,144,41611,476,058

1 Composite Factors:
exponentprime factorscomposite factordigitsbits*
315315215135588585700378401331530263461150195341135.260
P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2016-10-09T01:59:41kkmrkkblmbrbkManual testing200000000500000000012-
skipped known factor: 432857569
--0.369--41.267%


Trial Factoring results:
No TF results for M31531


ECM factoring results:

Old Calculation Method

Total ECM effort:19.209 GHz-days
Estimated T-Level:34.782
DigitsB1CurvesCompleteFacMiss
20110002377 / 10023.7700.000%
25500002377 / 2808.4890.020%
302500002096 / 6403.2753.772%
3510000001511 / 15800.95638.418%

New Calculation Method

Total ECM effort:19.209 GHz-days
Estimated T-Level:34.782
DigitsB1CompleteFacMiss
2011000273.6720.000%
255000051.0390.000%
302500007.5270.054%
3510000000.88841.142%
4030000000.08691.741%
45110000000.00799.282%


ECM Summary

B1B2factorcurvesGHz-days
5000050000002810.161
250000250000005851.681
10000001000000005115.873
10000001000000001,00011.49


Lucas-Lehmer results:
No L-L results for M31531


PRP results:
dateuseridcompidcofactorsres64PRP
2017-09-21T19:41:50Oliver KruseOliver-PCE47E53D4164117__?
2017-09-21T20:27:24Oliver KruseManual testingE47E53D4164117__?
2017-10-02T10:35:57kkmrkkblmbrbkManual testing
432857569
120481561651650369509914507935137
E47E53D4164117__no
2017-12-07T03:12:58ATHxps
432857569
120481561651650369509914507935137
E47E53D4164117__no
2020-04-17T13:47:34Oliver KruseManual testing
432857569
120481561651650369509914507935137
302C52F20704BC__no


P-1 factor-bounds graph:
B1 = 200000000, B2 = 5000000000 (P-1 stage 2)
B1 = 200000000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2020-04-17T13:47:34+00:00