is 2 2777821 - 1
has 836208 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-L21EF056F11E990EAdouble-checked
PRP9CE4AC1C18CBDC07verified PRP

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26821.457467.6471%2700000840000000.79847.6844%22.255970.1332%2.4861%
PrimeNet2590.027662.7119%120002200000.00262.8577%0.030363.7774%1.0656%
GPU722630.574665.0794%150002400000.00311.7472%0.577665.6895%0.6101%
Difference+5+20.8829+2.5677%+2685000+83760000+0.7954+5.9372%+21.6783+4.4437%+4.4437%

Known prime factors (1 factor, 75.0 bits, 0.00269976% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
2777821376360410716418802487512374.9956774381983511875
54 × 10839011173619
2020-11-25625108390111736192,192.766,136123,523

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-11-17T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.242%
2010-11-10T22:07:00Jocelyn LaroucheManual testing1500015000---0.002--0.210%
2010-11-27T16:47:00markrtiny1100002392500---0.026--2.614%
2016-08-06T20:01:40Jocelyn LaroucheManual testing15200047850006---0.045--3.235%
2016-12-18T19:43:08Jocelyn Larouchelow 4M182400182400---0.020--1.171%
2017-01-10T10:25:02Jocelyn Larouchelow 4M218880218880---0.025--1.286%
2017-01-10T10:25:06Jocelyn Larouchelow 4M262656262656---0.029--1.407%
2017-03-11T20:25:00Jocelyn Larouchelow 4M31518731518706---0.053--3.284%
2017-03-22T23:40:55mikrMSI27000008400000012---0.798--7.684%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2016-02-23T16:29:21Mark RoseManual testing21260--0.055--
2009-01-28T23:27:00Sturle Sundegigotte.ifi260261--0.055--
2012-03-28T15:32:00Grant McCrackenthumper261262--0.111--
2013-01-14T12:31:00dbaughManual testing262263--0.353--
2015-04-21T09:20:00VictordeHollanderManual testing263264--0.707--
2015-04-21T09:20:00VictordeHollanderManual testing264265--1.345--
2015-12-10T13:38:51omylistManual testing265266--2.690--
2017-10-14T11:30:24Gordon SpenceManual testing266267--5.380--
2019-02-24T11:40:39chuenkitManual testing267268--10.76--


ECM factoring results:

Old Calculation Method

Total ECM effort:6.139 GHz-days
Estimated T-Level:2.950
DigitsB1CurvesCompleteFacMiss
201100059 / 1000.59055.268%
255000059 / 2800.21180.970%

New Calculation Method

Total ECM effort:6.139 GHz-days
Estimated T-Level:2.950
DigitsB1CompleteFacMiss
20110001.90314.909%
25500000.17284.197%
302500000.01198.946%


ECM Summary

B1B2factorcurvesGHz-days
500005000000545.619
50000500000050.520


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-11-17T00:00:00ANONYMOUSv4_computers21EF056F11E990EA0.215
2018-08-24T21:47:06kkmrkkblmbrbkold21EF056F11E990EA0.215


PRP results:
dateuseridcompidcofactorsres64PRP
2020-11-26T05:20:02mrhx
37636041071641880248751
9CE4AC1C18CBDC07no


P-1 factor-bounds graph:
B1 = 2700000, B2 = 84000000 (P-1 stage 2)
B1 = 2700000 (P-1 stage 1)
B1 = 315187, B2 = 3151870 (P-1 stage 2)
B1 = 152000, B2 = 4785000 (P-1 stage 2)
B1 = 315187 (P-1 stage 1)
B1 = 262656 (P-1 stage 1)
B1 = 110000, B2 = 2392500 (P-1 stage 2)
B1 = 218880 (P-1 stage 1)
B1 = 182400 (P-1 stage 1)
B1 = 152000 (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: 2020-11-26T05:20:02+00:00