is 2 3857921 - 1
has 1161350 decimal digits
takes 0.405 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LA5B524EB9FDB1E8Adouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual2687.702167.1642%2000000620000000.80248.0345%8.504569.8024%2.6382%
PrimeNet2600.039863.3333%170003400000.00533.1961%0.045164.5053%1.1719%
GPU722640.922665.6250%240005000000.00762.2291%0.930266.3913%0.7663%
Difference+4+6.7795+1.5392%+1976000+61500000+0.7948+5.8054%+7.5743+3.4111%+3.4111%

Known prime factors (1 factor, 91.1 bits, 0.00236213% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
385792127078465256783627599596086632891.129350946342042561623211
3 × 72 × 181 × 2069 × 442439 × 14408903
2016-06-2044243914408903242,842,9820.18330.2233

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2000-10-15T00:00:00ANONYMOUSv4_computers5500055000---0.008--0.717%
2010-09-11T20:05:00markrtiny950001995000---0.030--2.879%
2016-06-20T04:36:42mikrMSI200000062000000122891.1290.8020.8101.6058.034%
2022-03-05T00:34:13Jocelyn LaroucheManual testing9000090000---0.014--0.966%
2022-03-22T17:36:11Jocelyn LaroucheManual testing100000100000---0.015--1.026%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2016-02-23T16:29:41Mark RoseManual testing21260--0.040--
2009-02-24T17:21:00S485122USB-Z260261--0.040--
2011-02-24T19:44:00markroldgamer261262--0.080--
2012-02-20T20:16:00GrunwalderGIMPManual testing21263--0.414--
2016-02-23T16:29:41Mark RoseManual testing262263--0.254--
2015-01-14T12:12:00VictordeHollanderManual testing263264--0.509--
2015-01-14T12:12:00VictordeHollanderManual testing264265--0.968--
2016-03-07T09:18:47ramgeisManual testing265266--1.937--
TF assumed completed to 67 but no detailed record exists
2022-01-22T13:05:31Jocelyn LaroucheManual testing267268--7.748--


ECM factoring results:

Old Calculation Method

Total ECM effort:1.353 GHz-days
Estimated T-Level:0.450
DigitsB1CurvesCompleteFacMiss
20110009 / 1000.09091.352%
25500009 / 2800.03296.831%

New Calculation Method

Total ECM effort:1.353 GHz-days
Estimated T-Level:0.450
DigitsB1CompleteFacMiss
20110000.29074.802%
25500000.02697.410%
302500000.00299.839%


ECM Summary

B1B2factorcurvesGHz-days
50000500000091.353


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-02-14T00:00:00ANONYMOUSv4_computers14B0FEEA7F3BF4__0.405
1999-08-31T00:00:00Dry Creek Photov4_computersA5B524EB9FDB1E8A0.405


PRP results:
dateuseridcompidcofactorsres64PRP
2017-09-20T06:43:31kkmrkkblmbrbkManual testing
2707846525678362759959608663
97E8684201A9D5__no
2017-12-26T13:42:13Oliver KruseGTX-0
2707846525678362759959608663
97E8684201A9D5__no


P-1 factor-bounds graph:
B1 = 2000000, B2 = 62000000 (P-1 stage 2)
B1 = 2000000 (P-1 stage 1)
B1 = 95000, B2 = 1995000 (P-1 stage 2)
B1 = 100000 (P-1 stage 1)
B1 = 95000 (P-1 stage 1)
B1 = 90000 (P-1 stage 1)
B1 = 55000 (P-1 stage 1)
103
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105
106
107
103
104
105
106
107
108
TF factor-bounds graph:
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266
265
264
263
262
261
260
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290
2100
Last modified: 2022-03-22T17:36:11+00:00