is 2 1666871 - 1
has 501779 decimal digits
takes 0.078 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L0DECF81395EB5EA1double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26717.826268.6567 %1000000400000000.21326.4374 %18.039470.6744 %
Target2610.184365.5738 %70004000000.00191.2063 %0.186265.9890 %
Difference+6+17.6419+3.0829 %+993000+39600000+0.2113+5.2311%+17.8532+4.6854 %

Known prime factors (1 factor, 72.3 bits, 0.00433761% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
166687158235610915364567657132272.3021746854163140536
23 × 312 × 59627 × 3810661
2012-02-16596273810661993.050.01800.0265

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2012-02-16AxonManual testing100000100000--0.0082.004%
2012-02-16AxonManual testing200000200000--0.0162.733%
2012-02-16AxonManual testing300000300000--0.0243.216%
2012-02-16AxonManual testing400000400000--0.0313.584%
2012-02-16AxonManual testing500000500000--0.0393.883%
2012-02-16AxonManual testing600000600000--0.0474.137%
2012-02-16AxonManual testing700000700000--0.0554.357%
2012-02-16AxonManual testing800000800000--0.0634.553%
2012-02-16AxonManual testing900000900000--0.0714.728%
2012-02-16AxonManual testing10000001000000--0.0794.888%
2012-02-16AxonManual testing10000001600000012--0.1439.314%
2012-02-16AxonManual testing10000002400000012--0.1779.952%
2012-02-16AxonManual testing10000003200000012--0.21210.404%
2012-02-16AxonManual testing10000004000000012--0.24610.753%
2016-03-17alpertronManual testing5000001500000012
skipped known factor: 5823561091536456765713
---8.776%


Trial Factoring results:
5758596061626364656667
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
1998-03-23ANONYMOUSv4_computers212560.006
1998-11-14Greg Hewgillv4_computers212570.012
2010-04-28Architects Cubedi4l_12602610.092
2010-08-22GrunwalderGIMPManual testing212630.957


ECM factoring results:
Total ECM effort:38.165 GHz-days
Estimated T-Level:25.718
DigitsB1CompleteFacMiss
201100014.6540.000%
25500001.67418.740%
302500000.14486.623%
3510000000.01099.005%


ECM Summary

B1B2factorcurvesGHz-days
10.068
50000500000025116.98
250000400000005021.11


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1998-03-23ANONYMOUSv4_computers0DECF81395EB5EA10.078
1998-11-21Greg Hewgillv4_computers0DECF81395EB5EA10.078


PRP results:
dateuseridcompidcofactorsres64
2017-10-02Oliver KruseGTX-1
5823561091536456765713
5CFAB46B3CDF0FA3
2017-11-03Chang Chia-Tchehomura
5823561091536456765713
5CFAB46B3CDF0FA3


CERT results:
No CERT results for M1666871


P-1 factor-bounds graph:
B1 = 1000000, B2 = 40000000 (P-1 stage 2)
B1 = 1000000, B2 = 32000000 (P-1 stage 2)
B1 = 1000000, B2 = 24000000 (P-1 stage 2)
B1 = 1000000, B2 = 16000000 (P-1 stage 2)
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 1000000 (P-1 stage 1)
B1 = 900000 (P-1 stage 1)
B1 = 800000 (P-1 stage 1)
B1 = 700000 (P-1 stage 1)
B1 = 600000 (P-1 stage 1)
B1 = 500000 (P-1 stage 1)
B1 = 400000 (P-1 stage 1)
B1 = 300000 (P-1 stage 1)
B1 = 200000 (P-1 stage 1)
B1 = 100000 (P-1 stage 1)
103
104
105
106
103
104
105
106
107
108
TF factor-bounds graph:
263
261
257
256
this exponent TF target: 61
TF double-checked to: 67
ECM T-Level=25.72 ~= 69-bit
250
260
270
280
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Last modified: 2024-03-13T02:15:48+00:00