is 2 2783687 - 1
has 837974 decimal digits
takes 0.215 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L6B1D7EC88C5A1E4Edouble-checked
PRP24B7FEB97BDF7601verified PRP

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26821.412267.6471%3000000900000000.86687.8321%22.279070.1810%2.5339%
PrimeNet2590.027662.7119%120002200000.00262.8588%0.030263.7778%1.0660%
GPU722630.573365.0794%150002400000.00311.7479%0.576465.6897%0.6104%
Difference+5+20.8389+2.5677%+2985000+89760000+0.8638+6.0842%+21.7026+4.4912%+4.4912%

Known prime factors (1 factor, 71.7 bits, 0.00257526% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
278368738021128105503861614412271.687682927500568560
24 × 3 × 5 × 13 × 23 × 67 × 142042193
2021-01-3167142042193321.240.86671.6187

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-11-17T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.242%
2010-11-11T04:19:00Jocelyn LaroucheManual testing1500015000---0.002--0.211%
2010-11-25T20:06:00markrtiny1000002075000---0.023--2.483%
2014-10-28T23:25:00Jocelyn LaroucheManual testing123057123057---0.014--0.946%
2016-05-03T01:41:40Jocelyn LaroucheManual testing20000036000006---0.043--3.183%
2017-07-20T22:03:20Jocelyn Larouchelow 4M40000040000006---0.067--3.575%
2019-11-14T10:43:13BigBrotherWinston30000009000000012---0.867--7.832%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2016-02-23T16:29:21Mark RoseManual testing21260--0.055--
2009-01-28T05:36:00Sturle Sundegimba.ifi260261--0.055--
2012-04-01T07:57:00Grant McCrackenhome261262--0.110--
2013-01-14T12:31:00dbaughManual testing262263--0.353--
2015-04-21T09:20:00VictordeHollanderManual testing263264--0.705--
2015-04-21T09:20:00VictordeHollanderManual testing264265--1.342--
2016-02-08T11:13:52ramgeisManual testing265266--2.684--
2017-10-16T21:21:14Gordon SpenceManual testing266267--5.369--
2019-02-25T02:38:33chuenkitManual testing267268--10.74--


ECM factoring results:

Old Calculation Method

Total ECM effort:6.974 GHz-days
Estimated T-Level:3.350
DigitsB1CurvesCompleteFacMiss
201100067 / 1000.67050.999%
255000067 / 2800.23978.685%

New Calculation Method

Total ECM effort:6.974 GHz-days
Estimated T-Level:3.350
DigitsB1CompleteFacMiss
20110002.16111.518%
25500000.19582.256%
302500000.01298.804%


ECM Summary

B1B2factorcurvesGHz-days
500005000000616.349
50000500000060.625


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-05-30T00:00:00ANONYMOUSv4_computers6B1D7EC88C5A1E4E0.215
2018-08-26T08:13:04kkmrkkblmbrbkold6B1D7EC88C5A1E4E0.215


PRP results:
dateuseridcompidcofactorsres64PRP
2021-01-31T12:35:04ViliamF3
3802112810550386161441
24B7FEB97BDF7601no


P-1 factor-bounds graph:
B1 = 3000000, B2 = 90000000 (P-1 stage 2)
B1 = 3000000 (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 = 2075000 (P-1 stage 2)
B1 = 200000 (P-1 stage 1)
B1 = 123057 (P-1 stage 1)
B1 = 100000 (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: 2021-01-31T12:35:04+00:00