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M12 870 553 Mersenne number exponent details
is 2 12870553 - 1
has 3874423 decimal digits
takes 5.257 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 PRP tests remaining
ResidueStatus
L-LBB3B303D10C000E4double-checked
PRP43686BD014F9692BPRP-tested

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual2684.631164.7059 %50000044627310014.68099.4991 %19.312068.0585 %
Target2684.631164.7059 %90000120000000.43763.1642 %5.068765.8227 %
Difference---+410000+434273100+14.2433+6.3350%+14.2433+2.2359 %

Known prime factors (1 factor, 68.5 bits, 0.00053257% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
128705534305782510214676940172168.54516727263040736
25 × 34 × 367 × 17584249
2018-01-07367175842498.28670.56761.0598

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2001-08-31ANONYMOUSv4_computers1600003360000--0.1983.744%
2023-10-16nordisweet16_30.8b14500000500000--0.2962.370%
2023-10-27nordisweet16_30.8b14500000446273100
skipped known factor: 430578251021467694017
--17.219.499%


Trial Factoring results:
575859606162636465666768
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
2000-07-12ANONYMOUSv4_computers212640.153
2013-06-02lycornManual testing2642650.290
2014-04-27NesowaManual testing2652660.581
2015-04-11ThaManual testing2662671.161
2018-01-07ramgeisManual testing267269
68.545
21
4.853


ECM factoring results:
Total ECM effort:0.621 GHz-days
Estimated T-Level:0.192
DigitsB1CompleteFacMiss
20110000.03896.227%
25500000.00499.645%


ECM Summary

B1B2factorcurvesGHz-days
50000500000010.621


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
2001-09-30ANONYMOUSv4_computersBB3B303D10C000E45.257
2004-09-16ANONYMOUSv4_computersBB3B303D10C000E45.257
2005-02-12ANONYMOUSv4_computersBB3B303D10C000E45.257


PRP results:
dateuseridcompidcofactorsres64
2022-05-22Gordon Spenceskylake
430578251021467694017
43686BD014F9692B


CERT results:
dateuseridcompid
2022-05-22Stixxy2650-v4


P-1 factor-bounds graph:
B1 = 500000, B2 = 446273100 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
B1 = 160000, B2 = 3360000 (P-1 stage 2)
B1 = 160000 (P-1 stage 1)
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102
103
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105
106
101
102
103
104
105
106
107
108
109
TF factor-bounds graph:
269
267
266
265
264
this exponent TF target: 68
TF double-checked to: 67
ECM T-Level=0.19 ~= -16-bit
250
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270