is 2 2566939 - 1
has 772726 decimal digits
takes 0.178 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LAFB17ADF18EC4379double-checked
PRPA708043E5926CFB4verified PRP

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26823.220267.6471%32000001120000000.91808.0781%24.138270.2606%2.6135%
PrimeNet2590.029962.7119%110002000000.00212.6885%0.032163.7144%1.0025%
GPU722630.621865.0794%120001800000.00211.4800%0.623965.5962%0.5168%
Difference+5+22.5985+2.5677%+3188000+111820000+0.9159+6.5981%+23.5143+4.6644%+4.6644%

Known prime factors (1 factor, 80.9 bits, 0.00315324% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
256693923220894236699770828577272580.942452307090988523117
23 × 347 × 56672984712257
2021-01-0234756672984712257150,253310,541580,004

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-10-23T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.237%
2003-11-08T00:00:00Team Prime Ribv4_computers15000198750---0.003--0.757%
2010-12-21T01:09:00Jocelyn LaroucheManual testing2000020000---0.002--0.265%
2011-01-03T22:20:00Jocelyn LaroucheManual testing3000030000---0.003--0.367%
2011-01-10T23:57:00Jocelyn LaroucheManual testing5000050000---0.005--0.532%
2011-04-15T19:11:00James HeinrichWHS1750004112500---0.039--3.172%
2016-05-25T02:37:19mikrMSI320000011200000012---0.918--8.078%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-03-26T00:00:00ANONYMOUSv4_computers21259--0.030--
2016-02-23T16:29:16Mark RoseManual testing259260--0.030--
2009-01-27T02:23:00Sturle Sundedittersdorf.ifi260261--0.060--
2012-06-17T14:43:00Sebastian HornbostelManual testing261262--0.120--
2013-01-23T08:30:00dbaughManual testing262263--0.382--
2015-02-23T17:24:00VictordeHollanderManual testing263264--0.765--
2015-02-23T17:24:00VictordeHollanderManual testing264265--1.456--
2015-11-08T21:03:02ramgeisManual testing265266--2.911--
2017-08-13T10:39:20Gordon SpenceManual testing266267--5.822--
2019-05-27T13:36:55TJAOIManual testing267268--11.64--


ECM factoring results:

Old Calculation Method

Total ECM effort:8.122 GHz-days
Estimated T-Level:4.400
DigitsB1CurvesCompleteFacMiss
201100088 / 1000.88041.295%
255000088 / 2800.31472.990%

New Calculation Method

Total ECM effort:8.122 GHz-days
Estimated T-Level:4.400
DigitsB1CompleteFacMiss
20110003.3853.389%
25500000.31373.113%
302500000.02098.044%


ECM Summary

B1B2factorcurvesGHz-days
500005000000857.845
50000500000030.277


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-04-13T00:00:00ANONYMOUSv4_computersAFB17ADF18EC43790.178
2018-06-15T23:18:50kkmrkkblmbrbkoldAFB17ADF18EC43790.178


PRP results:
dateuseridcompidcofactorsres64PRP
2021-01-03T03:01:31Niels_Mache_Nextcloudconf4-a
2322089423669977082857727
A708043E5926CFB4no


P-1 factor-bounds graph:
B1 = 3200000, B2 = 112000000 (P-1 stage 2)
B1 = 3200000 (P-1 stage 1)
B1 = 175000, B2 = 4112500 (P-1 stage 2)
B1 = 175000 (P-1 stage 1)
B1 = 50000 (P-1 stage 1)
B1 = 30000 (P-1 stage 1)
B1 = 15000, B2 = 198750 (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: 2021-01-03T03:01:31+00:00