is 2 6942781 - 1
has 2089986 decimal digits
takes 1.514 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LF18F7AC595F2A421double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual272137.745068.0556%40000004568186709.06528.0807%146.810270.6369%2.5813%
PrimeNet2630.229963.4921%280007000000.02043.1617%0.250364.6463%1.1543%
GPU722674.279865.6716%450009000000.02902.2375%4.308866.4397%0.7681%
Difference+5+133.4652+2.3839%+3955000+455918670+9.0362+5.8432%+142.5014+4.1971%+1.8132%

Known prime factors:
No known factors for M6942781

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2001-09-10T00:00:00Team Prime Ribv4_computers35000542500---0.020--0.922%
2002-03-16T00:00:00Team Prime Ribv4_computers35000542500---0.020--0.922%
2002-04-28T00:00:00Team Prime Ribv4_computers35000542500---0.020--0.922%
2002-07-14T00:00:00Team Prime Ribv4_computers35000542500---0.020--0.922%
2004-05-25T00:00:00Team Prime Ribv4_computers35000542500---0.020--0.922%
2007-02-05T00:00:00Team Prime Ribv4_computers35000542500---0.020--0.922%
2012-08-19T11:11:00NesowaEPC850001508750---0.051--1.566%
2018-03-16T10:51:12Squeeky_Squirreli5-5250U_16004050001235250012---0.334--3.412%
2021-11-07T02:26:01Seth_TrManual testing20000005800000012---1.597--5.520%
2021-12-02T18:03:53Seth_TrManual testing4000000456818670---9.065--8.081%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-07-21T00:00:00ANONYMOUSv4_computers21262--0.088--
2004-02-07T00:00:00Sturle Sundev4_computers21263--0.230--
2014-02-09T10:11:00NesowaManual testing263264--0.283--
2014-02-16T12:44:00lycornManual testing264265--0.538--
2015-06-26T13:39:00VictordeHollanderManual testing265266--1.076--
2016-04-05T22:46:24Gordon SpenceManual testing266267--2.153--
2018-05-23T10:48:29ramgeisManual testing267268--4.305--
2020-04-24T07:21:04TJAOIManual testing268269--8.611--
2021-07-28T22:40:44takahashiManual testing269270--17.22--
2021-08-11T16:42:23SRBaseManual testing270271--34.44--
2021-09-26T07:27:20SRBaseManual testing271272--68.89--


ECM factoring results:
Total ECM effort:1.989 GHz-days
Estimated T-Level:1.154
DigitsB1CompleteFacMiss
20110000.23179.392%
25500000.02197.887%
302500000.00199.865%


ECM Summary

B1B2factorcurvesGHz-days
50000500000061.989


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-09-07T00:00:00ANONYMOUSv4_computersF18F7AC595F2A4211.514
2001-09-16T00:00:00Team Prime Ribv4_computersF18F7AC595F2A4211.514
2002-03-16T00:00:00Team Prime Ribv4_computersF18F7AC595F2A4211.514
2002-04-28T00:00:00Team Prime Ribv4_computersF18F7AC595F2A4211.514
2002-07-14T00:00:00Team Prime Ribv4_computersF18F7AC595F2A4211.514
2004-05-25T00:00:00Team Prime Ribv4_computersF18F7AC595F2A4211.514
2007-02-05T00:00:00Team Prime Ribv4_computersF18F7AC595F2A4211.514


PRP results:
No PRP results for M6942781


P-1 factor-bounds graph:
B1 = 4000000, B2 = 456818670 (P-1 stage 2)
B1 = 2000000, B2 = 58000000 (P-1 stage 2)
B1 = 4000000 (P-1 stage 1)
B1 = 2000000 (P-1 stage 1)
B1 = 405000, B2 = 12352500 (P-1 stage 2)
B1 = 405000 (P-1 stage 1)
B1 = 85000, B2 = 1508750 (P-1 stage 2)
B1 = 85000 (P-1 stage 1)
B1 = 35000, B2 = 542500 (P-1 stage 2)
B1 = 35000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2021-12-02T18:03:53+00:00