is 2 2618881 - 1
has 788362 decimal digits
takes 0.202 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LD8C2E9AA3128BDA4double-checked
PRPFDB20DA09489CC2Dverified PRP

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26945.586968.1159%2618881261888100.43715.6951%46.024169.9318%1.8158%
PrimeNet2590.029362.7119%110002000000.00242.6985%0.031763.7181%1.0062%
GPU722630.609465.0794%120002000000.00251.5325%0.611965.6145%0.5352%
Difference+6+44.9775+3.0366%+2606881+25988810+0.4346+4.1625%+45.4121+4.3172%+4.3172%

Known prime factors (1 factor, 89.5 bits, 0.00341712% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
26188818694464549981775361206479772789.490165995792668352921748
22 × 3 × 1181 × 146347 × 80035398697
2021-09-231463478003539869786,294,423488.36912.10

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-10-31T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.192%
2003-11-08T00:00:00Team Prime Ribv4_computers15000217500---0.003--0.667%
2010-11-17T22:12:00Jocelyn LaroucheManual testing2000020000---0.002--0.223%
2010-12-12T11:23:00markrtiny1000002125000---0.024--2.194%
2014-10-13T22:29:00Jocelyn LaroucheManual testing124508124508---0.014--0.819%
2016-05-24T01:15:57Jocelyn LaroucheManual testing20000036000006---0.043--2.826%
2017-07-20T22:03:19Jocelyn Larouchelow 4M40000040000006---0.067--3.195%
2019-10-14T15:57:33masserManual testing26188812618881012---0.437--5.695%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-03-26T00:00:00ANONYMOUSv4_computers21259--0.029--
2016-02-23T16:29:17Mark RoseManual testing259260--0.029--
2009-01-30T23:44:00Sturle Sundegiovanni.ifi260261--0.059--
2012-06-18T09:08:00markroldgamer261262--0.117--
2013-01-14T11:57:00dbaughManual testing262263--0.375--
2015-02-18T11:41:00VictordeHollanderManual testing263264--0.750--
2015-02-18T11:41:00VictordeHollanderManual testing264265--1.427--
2016-01-17T23:07:15ramgeisManual testing265266--2.853--
2017-08-30T11:24:05Gordon SpenceManual testing266267--5.707--
2019-04-15T13:43:00TJAOIManual testing267268--11.41--
2021-05-19T10:50:02TJAOIManual testing268269--22.83--


ECM factoring results:

Old Calculation Method

Total ECM effort:12.959 GHz-days
Estimated T-Level:22.161
DigitsB1CurvesCompleteFacMiss
2011000121 / 1001.21029.639%
2550000121 / 2800.43264.861%

New Calculation Method

Total ECM effort:12.959 GHz-days
Estimated T-Level:22.161
DigitsB1CompleteFacMiss
20110003.9961.840%
25500000.36569.450%
302500000.02397.750%
3510000000.00199.894%


ECM Summary

B1B2factorcurvesGHz-days
50000500000010711.03
50000500000020.206
50000675000070.829
766201000000050.893


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-07-26T00:00:00ANONYMOUSv4_computersD8C2E9AA3128BDA40.202
2000-04-27T00:00:00ANONYMOUSv4_computersD8C2E9AA3128BDA40.202
2018-07-07T08:55:19kkmrkkblmbrbkoldD8C2E9AA3128BDA40.202


PRP results:
dateuseridcompidcofactorsres64PRP
2021-09-25T14:03:31GANLMS-11
869446454998177536120647977
FDB20DA09489CC2Dno


P-1 factor-bounds graph:
B1 = 2618881, B2 = 26188810 (P-1 stage 2)
B1 = 2618881 (P-1 stage 1)
B1 = 400000, B2 = 4000000 (P-1 stage 2)
B1 = 400000 (P-1 stage 1)
B1 = 200000, B2 = 3600000 (P-1 stage 2)
B1 = 100000, B2 = 2125000 (P-1 stage 2)
B1 = 200000 (P-1 stage 1)
B1 = 124508 (P-1 stage 1)
B1 = 100000 (P-1 stage 1)
B1 = 15000, B2 = 217500 (P-1 stage 2)
B1 = 20000 (P-1 stage 1)
B1 = 15000 (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: 2021-09-25T14:03:31+00:00