is 2 2808427 - 1
has 845421 decimal digits
takes 0.217 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L-unknown--unknown-
PRPF42C6A0149251C81verified PRP

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26821.223667.6471%50000002000000001.74989.1610%22.973470.6109%2.9639%
PrimeNet2590.027362.7119%120002400000.00272.9287%0.030163.8039%1.0921%
GPU722630.568365.0794%150002600000.00321.7908%0.571565.7047%0.6253%
Difference+5+20.6553+2.5677%+4985000+199740000+1.7466+7.3703%+22.4019+4.9062%+4.9062%

Known prime factors (1 factor, 70.0 bits, 0.00249294% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
280842711907910483028286266172270.012212003204694804
22 × 33 × 709 × 2768677907
2020-09-277092768677907113.1716.89431.552

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-11-28T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.243%
2010-11-12T22:13:00Jocelyn LaroucheManual testing1500015000---0.002--0.211%
2010-12-19T01:13:00markrtiny1100002447500---0.027--2.632%
2016-08-01T15:21:51Jocelyn LaroucheManual testing18200048950006---0.049--3.357%
2016-12-29T21:56:32Jocelyn Larouchelow 4M218400218400---0.024--1.287%
2017-05-13T16:00:13Jocelyn Larouchelow 4M36400036400006---0.061--3.463%
2019-11-12T01:51:53BigBrotherWinston30000009000000012---0.867--7.839%
2019-11-13T13:54:45masserManual testing30000003000000012---0.501--6.479%
2020-01-11T17:53:48masserManual testing500000020000000012---1.750--9.161%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2016-02-23T16:29:22Mark RoseManual testing21260--0.055--
2009-02-13T16:23:00Sturle Sundefungo.ifi260261--0.055--
2012-02-24T04:45:00markroldgamer261262--0.109--
2013-01-10T10:21:00dbaughManual testing262263--0.350--
2015-04-21T09:19:00VictordeHollanderManual testing263264--0.699--
2015-04-21T09:19:00VictordeHollanderManual testing264265--1.330--
2016-02-11T09:59:19ramgeisManual testing265266--2.661--
2017-10-24T17:48:47Gordon SpenceManual testing266267--5.322--
2018-12-30T14:49:39chuenkitManual testing267268--10.64--


ECM factoring results:

Old Calculation Method

Total ECM effort:3.961 GHz-days
Estimated T-Level:1.900
DigitsB1CurvesCompleteFacMiss
201100038 / 1000.38068.255%
255000038 / 2800.13687.288%

New Calculation Method

Total ECM effort:3.961 GHz-days
Estimated T-Level:1.900
DigitsB1CompleteFacMiss
20110001.22629.352%
25500000.11189.513%
302500000.00799.320%


ECM Summary

B1B2factorcurvesGHz-days
500005000000373.857
50000500000010.104


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-05-02T00:00:00ANONYMOUSv4_computers195477753E59DC__0.217


PRP results:
dateuseridcompidcofactorsres64PRP
2020-09-27T11:07:30M Millercruncher
1190791048302828626617
F42C6A0149251C81no


P-1 factor-bounds graph:
B1 = 5000000, B2 = 200000000 (P-1 stage 2)
B1 = 3000000, B2 = 90000000 (P-1 stage 2)
B1 = 5000000 (P-1 stage 1)
B1 = 3000000, B2 = 30000000 (P-1 stage 2)
B1 = 3000000 (P-1 stage 1)
B1 = 364000, B2 = 3640000 (P-1 stage 2)
B1 = 182000, B2 = 4895000 (P-1 stage 2)
B1 = 364000 (P-1 stage 1)
B1 = 110000, B2 = 2447500 (P-1 stage 2)
B1 = 218400 (P-1 stage 1)
B1 = 182000 (P-1 stage 1)
B1 = 110000 (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: 2020-09-27T11:07:30+00:00