is 2 17256787 - 1
has 5194811 decimal digits
takes 9.827 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LEC9CF26AC87D0A81double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual2671.721962.6866%43000090000000.74065.9238%2.462464.8969%2.2104%
PrimeNet2650.422861.5385%8000024000000.17044.5397%0.593263.2845%1.7460%
GPU722696.918363.7681%12000032000000.23763.3024%7.155964.9646%1.1965%
Difference-2-5.1964-1.0815%+310000+5800000+0.5029+2.6214%-4.6934-0.0677%-0.0677%

Known prime factors (1 factor, 75.2 bits, 0.00043581% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
17256787436084713593271451604712375.2071263516532924905
32 × 5 × 74 × 11694354509
2017-12-27240111694354509453.49526.09982.58

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2002-12-02T00:00:00Ryan Malayterv4_computers275000275000---0.227--2.172%
2017-06-12T21:26:48riccardo ubertiDuallie-2430000900000012---0.741--5.924%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2001-02-18T00:00:00Net_Forcev4_computers21258--0.002--
2001-04-01T00:00:00Net_Forcev4_computers21259--0.004--
2001-08-24T00:00:00tscv4_computers21265--0.423--
2013-09-23T23:50:00David CampeauManual testing265266--0.433--
2014-09-05T00:08:00NesowaManual testing266267--0.866--


ECM factoring results:

Old Calculation Method

Total ECM effort:0.866 GHz-days
Estimated T-Level:0.050
DigitsB1CurvesCompleteFacMiss
20110001 / 1000.01099.000%
25500001 / 2800.00499.643%

New Calculation Method

Total ECM effort:0.866 GHz-days
Estimated T-Level:0.050
DigitsB1CompleteFacMiss
20110000.03896.227%
25500000.00499.645%


ECM Summary

B1B2factorcurvesGHz-days
50000500000010.866


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
2003-01-16T00:00:00Ryan Malayterv4_computersEC9CF26AC87D0A819.83
2006-05-29T00:00:00ANONYMOUSv4_computersEC9CF26AC87D0A819.83


PRP results:
dateuseridcompidcofactorsres64PRP
2019-10-03T19:23:13riccardo ubertiNomad2C
43608471359327145160471
792B7D94A2BC7BC7no
2020-08-08T04:41:30JaytholomewJaytholomew
43608471359327145160471
792B7D94A2BC7BC7no


P-1 factor-bounds graph:
B1 = 430000, B2 = 9000000 (P-1 stage 2)
B1 = 430000 (P-1 stage 1)
B1 = 275000 (P-1 stage 1)
102
103
104
105
106
102
103
104
105
106
107
108
109
1010
1011
TF factor-bounds graph:
267
266
265
259
258
250
260
270
280
290
2100
Last modified: 2020-08-08T04:41:30+00:00