is 2 2608873 - 1
has 785350 decimal digits
takes 0.181 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L777D2BF6B55CE160double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26822.847067.6471%3000000900000000.77847.7818%23.625470.1647%2.5176%
PrimeNet2590.029462.7119%110002000000.00212.6966%0.031663.7174%1.0055%
GPU722630.611865.0794%120002000000.00221.5314%0.614065.6141%0.5348%
Difference+5+22.2352+2.5677%+2988000+89800000+0.7762+6.2504%+23.0114+4.5506%+4.5506%

Known prime factors (1 factor, 82.6 bits, 0.00316562% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
260887372641760098155214924045032582.5871392205755093391187
277 × 5026013556293831
2020-07-052775026013556293831584,04027,540,18151,437,388

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-10-31T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.238%
2003-11-08T00:00:00Team Prime Ribv4_computers15000217500---0.003--0.781%
2010-11-17T11:34:00Jocelyn LaroucheManual testing2000020000---0.002--0.266%
2010-12-15T10:17:00markrtiny1000002125000---0.021--2.472%
2014-10-10T20:28:00Jocelyn LaroucheManual testing124602124602---0.013--0.941%
2016-05-19T05:28:34Jocelyn LaroucheManual testing20000036000006---0.039--3.154%
2017-07-10T01:11:34Jocelyn Larouchelow 4M40000040000006---0.060--3.545%
2019-12-03T14:18:39masserManual testing20000005000000012---0.464--6.847%
2019-12-05T17:16:50BigBrotherWinston30000009000000012---0.778--7.782%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-03-26T00:00:00ANONYMOUSv4_computers21259--0.029--
2016-02-23T16:29:17Mark RoseManual testing259260--0.029--
2009-01-31T14:34:00Sturle Sundeghia.ifi260261--0.059--
2012-06-29T19:48:00Grant McCrackenthumper261262--0.118--
2013-01-14T11:55:00dbaughManual testing262263--0.376--
2015-02-18T11:41:00VictordeHollanderManual testing263264--0.753--
2015-02-18T11:41:00VictordeHollanderManual testing264265--1.432--
2016-01-15T14:57:04ramgeisManual testing265266--2.864--
2017-08-24T10:53:49Gordon SpenceManual testing266267--5.729--
2019-05-06T12:23:23TJAOIManual testing267268--11.46--


ECM factoring results:

Old Calculation Method

Total ECM effort:3.238 GHz-days
Estimated T-Level:1.750
DigitsB1CurvesCompleteFacMiss
201100035 / 1000.35070.345%
255000035 / 2800.12588.230%

New Calculation Method

Total ECM effort:3.238 GHz-days
Estimated T-Level:1.750
DigitsB1CompleteFacMiss
20110001.12932.335%
25500000.10290.299%
302500000.00699.374%


ECM Summary

B1B2factorcurvesGHz-days
500005000000333.053
50000500000020.185


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-04-23T00:00:00ANONYMOUSv4_computers777D2BF6B55CE1600.181
2018-06-28T21:28:00kkmrkkblmbrbkold777D2BF6B55CE1600.181


PRP results:
dateuseridcompidcofactorsres64PRP
2020-07-05T08:47:01Christoph ZengerManual testing
7264176009815521492404503
5A436610D9257718no
2020-07-05T10:14:35CrypticCluecruncher
7264176009815521492404503
5A436610D9257718no


P-1 factor-bounds graph:
B1 = 3000000, B2 = 90000000 (P-1 stage 2)
B1 = 2000000, B2 = 50000000 (P-1 stage 2)
B1 = 3000000 (P-1 stage 1)
B1 = 2000000 (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 = 124602 (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: 2020-07-05T10:14:35+00:00