is 2 2061287 - 1
has 620510 decimal digits
takes 0.136 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L380AC892E9C578AEdouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26828.916369.1176%25000001250000000.87467.8837%29.791071.5523%2.4347%
PrimeNet2580.018663.7931%90001600000.00162.6684%0.020364.7592%0.9661%
GPU722620.298066.1290%90001300000.00151.3652%0.299566.5914%0.4624%
Difference+6+28.6183+2.9886%+2491000+124870000+0.8732+6.5185%+29.4914+4.9609%+4.9609%

Known prime factors (1 factor, 69.7 bits, 0.00338086% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
20612879518469869405593950472169.689230886574004629
83 × 2917 × 953639339
2020-02-222917953639339101.474.95379.2516

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-02-24T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.222%
2009-06-21T23:19:00harleeT7500_220020000260000---0.003--0.874%
2010-12-26T02:29:00Jocelyn LaroucheManual testing3000030000---0.003--0.350%
2011-01-06T01:06:00Jocelyn LaroucheManual testing5000050000---0.005--0.508%
2011-01-21T08:26:00James Heinrichi7-9201350002902500---0.027--2.717%
2014-10-26T01:00:00Jocelyn LaroucheManual testing166138166138---0.016--1.058%
2016-06-26T03:50:55Jocelyn LaroucheManual testing182751580500012---0.047--3.336%
2016-09-29T01:45:03Jocelyn Larouchelow 4M1827511393200012---0.089--3.954%
2016-11-04T00:18:42Jocelyn Larouchelow 4M219301219301---0.021--1.224%
2016-11-04T12:39:35Jocelyn Larouchelow 4M263161263161---0.025--1.341%
2016-11-07T03:11:24Jocelyn Larouchelow 4M315793315793---0.030--1.465%
2017-02-20T01:26:55mikrMSI250000012500000012---0.875--7.884%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-01-10T00:00:00ANONYMOUSv4_computers21258--0.019--
2016-02-23T16:29:04Mark RoseManual testing258260--0.056--
2009-01-02T19:45:00Sturle Sundegouffy.ifi260261--0.075--
2012-03-12T21:47:00Sebastian HornbostelManual testing261262--0.149--
2013-09-01T20:20:00ramgeisManual testing262263--0.476--
2015-04-21T09:19:00VictordeHollanderManual testing263264--0.952--
2015-04-21T09:19:00VictordeHollanderManual testing264265--1.813--
2015-11-03T10:10:01ramgeisManual testing265266--3.625--
2016-08-29T15:06:16Gordon SpenceManual testing266267--7.251--
2019-03-25T04:48:54chuenkitManual testing267268--14.50--


ECM factoring results:

Old Calculation Method

Total ECM effort:5.858 GHz-days
Estimated T-Level:3.450
DigitsB1CurvesCompleteFacMiss
201100069 / 1000.69049.984%
255000069 / 2800.24678.124%

New Calculation Method

Total ECM effort:5.858 GHz-days
Estimated T-Level:3.450
DigitsB1CompleteFacMiss
20110002.22610.798%
25500000.20181.778%
302500000.01298.769%


ECM Summary

B1B2factorcurvesGHz-days
500005000000665.603
50000500000030.255


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1998-05-01T00:00:00ANONYMOUSv4_computers380AC892E9C578AE0.136
1999-02-14T00:00:00ANONYMOUSv4_computers380AC892E9C578AE0.136


PRP results:
dateuseridcompidcofactorsres64PRP
2020-02-23T10:34:43Jinyuan WangManual testing
951846986940559395047
08E90D17C140B61Eno
2020-02-25T05:47:48James HeinrichC2750
951846986940559395047
08E90D17C140B61Eno


P-1 factor-bounds graph:
B1 = 2500000, B2 = 125000000 (P-1 stage 2)
B1 = 2500000 (P-1 stage 1)
B1 = 182751, B2 = 13932000 (P-1 stage 2)
B1 = 182751, B2 = 5805000 (P-1 stage 2)
B1 = 315793 (P-1 stage 1)
B1 = 135000, B2 = 2902500 (P-1 stage 2)
B1 = 263161 (P-1 stage 1)
B1 = 219301 (P-1 stage 1)
B1 = 182751 (P-1 stage 1)
B1 = 166138 (P-1 stage 1)
B1 = 135000 (P-1 stage 1)
B1 = 50000 (P-1 stage 1)
B1 = 20000, B2 = 260000 (P-1 stage 2)
B1 = 30000 (P-1 stage 1)
B1 = 20000 (P-1 stage 1)
B1 = 2048, B2 = 204800 (P-1 stage 2)
B1 = 2048 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2020-02-25T05:47:48+00:00