is 2 2028227 - 1
has 610558 decimal digits
takes 0.133 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L76A5D391BAB49B9Bdouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26829.387769.1176%40000002000000001.39948.7520%30.787171.8205%2.7028%
PrimeNet2580.018963.7931%90001500000.00162.6140%0.020564.7395%0.9464%
GPU722620.302966.1290%80001200000.00131.2744%0.304266.5607%0.4317%
Difference+6+29.0848+2.9886%+3992000+199880000+1.3981+7.4776%+30.4828+5.2598%+5.2598%

Known prime factors (1 factor, 85.2 bits, 0.00420201% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
2028227452527809453367440806793192685.22611155748578767747417
3 × 433 × 8587951176880483
2020-02-2543385879511768804835,667,07244,607,96583,315,257

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-02-24T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.221%
2007-11-17T00:00:00markrv4_computers2000003500000---0.036--3.026%
2010-12-14T09:47:00Jocelyn LaroucheManual testing202822202822---0.019--1.173%
2013-10-19T08:50:00David Campeaui5-2500k58000015080000---0.131--4.747%
2019-04-11T05:59:44mikrMSI400000020000000012---1.399--8.752%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-01-02T00:00:00ANONYMOUSv4_computers21258--0.019--
2016-02-23T16:29:03Mark RoseManual testing258260--0.057--
2009-01-03T08:37:00Sturle Sundegehry.ifi260261--0.076--
2012-02-07T06:47:00Sebastian HornbostelManual testing261262--0.151--
2013-02-21T00:57:00dbaughManual testing262263--0.484--
2015-04-13T20:08:00VictordeHollanderManual testing263264--0.968--
2015-04-13T20:08:00VictordeHollanderManual testing264265--1.842--
2015-10-31T16:44:09ramgeisManual testing265266--3.684--
2016-07-06T22:01:14Gordon SpenceManual testing266267--7.369--
2019-03-20T02:02:07chuenkitManual testing267268--14.74--


ECM factoring results:

Old Calculation Method

Total ECM effort:6.270 GHz-days
Estimated T-Level:3.700
DigitsB1CurvesCompleteFacMiss
201100074 / 1000.74047.534%
255000074 / 2800.26476.739%

New Calculation Method

Total ECM effort:6.270 GHz-days
Estimated T-Level:3.700
DigitsB1CompleteFacMiss
20110002.3879.190%
25500000.21680.594%
302500000.01398.680%


ECM Summary

B1B2factorcurvesGHz-days
500005000000726.100
50000500000020.169


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-01-10T00:00:00ANONYMOUSv4_computers76A5D391BAB49B9B0.133
2016-07-15T15:20:48Mark Rosedonatello76A5D391BAB49B9B0.133


PRP results:
dateuseridcompidcofactorsres64PRP
2020-02-26T07:51:58Christoph ZengerManual testing
45252780945336744080679319
F0BF97E55C631541no
2020-02-27T00:08:16Jinyuan WangManual testing
45252780945336744080679319
F0BF97E55C631541no
2020-02-28T16:50:15Chang Chia-Tcheexbbbe-lt
45252780945336744080679319
F0BF97E55C631541no


P-1 factor-bounds graph:
B1 = 4000000, B2 = 200000000 (P-1 stage 2)
B1 = 4000000 (P-1 stage 1)
B1 = 580000, B2 = 15080000 (P-1 stage 2)
B1 = 580000 (P-1 stage 1)
B1 = 200000, B2 = 3500000 (P-1 stage 2)
B1 = 202822 (P-1 stage 1)
B1 = 200000 (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: 2020-02-28T16:50:15+00:00