is 2 6918649 - 1
has 2082721 decimal digits
takes 1.509 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LD28BD8F4A8E803D8double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual272138.225568.0556%40000004567054809.06328.0777%147.288770.6359%
Target2674.294865.6716%450009000000.02902.2362%4.323766.4393%
Difference+5+133.9307+2.3839%+3955000+455805480+9.0342+5.8415%+142.9650+4.1966%

Known prime factors:
No known factors for M6918649

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2002-01-28ANONYMOUSv4_computers35000341250---0.016--0.798%
2011-11-21James Heinrichi7-9201300002665000---0.085--1.986%
2020-01-11takahashivaio6000001200000012---0.386--3.581%
2021-11-29Seth_TrManual testing4000000456705480---9.063--8.078%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-07-29ANONYMOUSv4_computers21262--0.089--
2005-02-12ANONYMOUSv4_computers21263--0.231--
2014-02-09NesowaManual testing263264--0.284--
2014-02-17lycornManual testing264265--0.540--
2015-06-26VictordeHollanderManual testing265266--1.080--
2016-04-02Gordon SpenceManual testing266267--2.160--
2018-02-27-Anonymous-Manual testing267268--4.320--
2020-05-15TJAOIManual testing268269--8.641--
2021-07-18takahashiManual testing269270--17.28--
2021-08-11SRBaseManual testing270271--34.56--
2021-09-25SRBaseManual testing271272--69.13--


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)
1999-06-26foxkidv4_computersD28BD8F4A8E803D81.509
2002-02-03ANONYMOUSv4_computersD28BD8F4A8E803D81.509


PRP results:
No PRP results for M6918649


P-1 factor-bounds graph:
B1 = 4000000, B2 = 456705480 (P-1 stage 2)
B1 = 4000000 (P-1 stage 1)
B1 = 600000, B2 = 12000000 (P-1 stage 2)
B1 = 600000 (P-1 stage 1)
B1 = 130000, B2 = 2665000 (P-1 stage 2)
B1 = 130000 (P-1 stage 1)
B1 = 35000, B2 = 341250 (P-1 stage 2)
B1 = 35000 (P-1 stage 1)
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109
TF factor-bounds graph:
272
271
270
269
268
267
266
265
264
263
262
this exponent TF target: 67
TF double-checked to: 67.7
ECM T-Level=1.15 ~= -13-bit
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Last modified: 2023-03-23T17:39:31+00:00