is 2 1877857 - 1
has 565292 decimal digits
takes 0.102 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
Actual26715.823368.6567%500000150000000.10155.0844%15.924870.2503%1.5936%
PrimeNet2570.010263.1579%90001600000.00143.0314%0.011664.2747%1.1168%
GPU722610.163665.5738%100001500000.00141.6911%0.165066.1559%0.5822%
Difference+6+15.6597+3.0829%+490000+14850000+0.1001+3.3933%+15.7598+4.0944%+4.0944%

Known prime factors (3 factors, 140.3 bits, 0.00747340% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
187785789686450331033.0622388
22 × 3 × 199
-41999.244e-101.150e-61.597e-6
1877857829562108331136.27222088
23 × 11 × 251
2008-07-15112518.682e-91.894e-62.043e-6
187785723709458841465411321832271.006631290317672363
79 × 88853 × 89935249
2020-10-118885389935249282.320.39200.7199

4 Composite Factors:
exponentprime factorscomposite factordigitsbits*
18778577440048082438862424892169.334
18778572126417202736266956928325939703932104.068
187785719668468663889405842907946953843933107.278
1877857176399513789107866174317536723819573992348743140.340
P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2016-03-16T12:39:01alpertronManual testing5000001500000012-
skipped known factor: 8968645033
skipped known factor: 82956210833
--0.101--5.084%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2008-07-15T07:47:00J FeitsmaManual testing??36.272113.80720e-90.2178.12414e-9


ECM factoring results:

Old Calculation Method

Total ECM effort:19.910 GHz-days
Estimated T-Level:24.589
DigitsB1CurvesCompleteFacMiss
2011000257 / 1002.5707.555%
2550000257 / 2800.91839.872%

New Calculation Method

Total ECM effort:19.910 GHz-days
Estimated T-Level:24.589
DigitsB1CompleteFacMiss
20110008.8010.015%
25500000.79745.060%
302500000.04995.189%
3510000000.00299.774%


ECM Summary

B1B2factorcurvesGHz-days
500005000030.126
500005000000312.147
50000500000030.208
50000660000021616.88
50000675000070.553


Lucas-Lehmer results:
No L-L results for M1877857


PRP results:
dateuseridcompidcofactorsres64PRP
2017-10-04T13:03:56Oliver KruseGTX-2
8968645033
82956210833
3BA075740DDF1E__no
2017-11-08T01:15:57ATHec2-1xf
8968645033
82956210833
3BA075740DDF1E__no
2020-10-11T07:26:26M Millercruncher
8968645033
82956210833
2370945884146541132183
D84DEB4D137718FFno


P-1 factor-bounds graph:
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
100
101
102
103
104
105
106
100
101
102
103
104
105
106
107
108
TF factor-bounds graph:
267
2
230
240
250
260
270
280
290
2100
Last modified: 2021-09-29T12:10:54+00:00