is 2 6978709 - 1
has 2100801 decimal digits
takes 1.522 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LB8D67DF8C0A2AB55double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual272137.035968.0556%1000000300000000.81574.5636%137.851669.5134%
Target2674.257865.6716%450009000000.02902.2394%4.286866.4404%
Difference+5+132.7781+2.3839%+955000+29100000+0.7868+2.3242%+133.5649+3.0730%

Known prime factors:
No known factors for M6978709

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2001-09-16ANONYMOUSv4_computers35000525000---0.020--0.914%
2012-08-24NesowaEPC850001508750---0.051--1.567%
2019-05-05takahashivaio30000050000006---0.176--2.685%
2021-07-05takahashivaio10000003000000012---0.816--4.564%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-08-09Stephan Gruppv4_computers21262--0.088--
2005-08-16ANONYMOUSv4_computers21263--0.229--
2014-02-09NesowaManual testing263264--0.281--
2014-02-15lycornManual testing264265--0.535--
2015-07-03VictordeHollanderManual testing265266--1.071--
2016-04-26Gordon SpenceManual testing266267--2.142--
2018-02-27-Anonymous-Manual testing267268--4.283--
2020-04-24TJAOIManual testing268269--8.566--
2021-08-09takahashiManual testing269270--17.13--
2021-09-06SRBaseManual testing270271--34.27--
2021-09-25SRBaseManual testing271272--68.53--


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)
1999-06-15ANONYMOUSv4_computersB8D67DF8C0A2AB551.522
2001-10-06ANONYMOUSv4_computersB8D67DF8C0A2AB551.522


PRP results:
No PRP results for M6978709


P-1 factor-bounds graph:
B1 = 1000000, B2 = 30000000 (P-1 stage 2)
B1 = 1000000 (P-1 stage 1)
B1 = 300000, B2 = 5000000 (P-1 stage 2)
B1 = 300000 (P-1 stage 1)
B1 = 85000, B2 = 1508750 (P-1 stage 2)
B1 = 85000 (P-1 stage 1)
B1 = 35000, B2 = 525000 (P-1 stage 2)
B1 = 35000 (P-1 stage 1)
103
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105
106
103
104
105
106
107
108
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: 2021-09-25T07:18:41+00:00