is 2 6947861 - 1
has 2091515 decimal digits
takes 1.515 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LB52C3813E90EA9D7double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual272137.644368.0556%1000000300000000.81574.5613%138.460169.5126%
Target2674.276765.6716%450009000000.02902.2378%4.305766.4398%
Difference+5+133.3676+2.3839%+955000+29100000+0.7868+2.3235%+134.1544+3.0728%

Known prime factors:
No known factors for M6947861

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2001-09-10ANONYMOUSv4_computers35000472500---0.019--0.885%
2003-01-09ANONYMOUSv4_computers850001551250---0.052--1.577%
2019-05-07takahashivaio30000050000006---0.176--2.683%
2021-06-13takahashivaio10000003000000012---0.816--4.561%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-08-30ANONYMOUSv4_computers21262--0.088--
2003-01-09ANONYMOUSv4_computers21263--0.230--
2014-02-09NesowaManual testing263264--0.283--
2014-02-16lycornManual testing264265--0.538--
2015-06-26VictordeHollanderManual testing265266--1.076--
2016-04-05Gordon SpenceManual testing266267--2.151--
2018-02-26-Anonymous-Manual testing267268--4.302--
2020-04-10TJAOIManual testing268269--8.604--
2021-07-28takahashiManual testing269270--17.21--
2021-08-11SRBaseManual testing270271--34.42--
2021-10-10SRBaseManual testing271272--68.83--


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)
1999-04-02Stephen Woodv4_computers651ED3A2654C23__1.515
1999-06-26ANONYMOUSv4_computersB52C3813E90EA9D71.515
2001-09-22ANONYMOUSv4_computersB52C3813E90EA9D71.515
2003-05-04ANONYMOUSv4_computersB52C3813E90EA9D71.515


PRP results:
No PRP results for M6947861


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 = 1551250 (P-1 stage 2)
B1 = 85000 (P-1 stage 1)
B1 = 35000, B2 = 472500 (P-1 stage 2)
B1 = 35000 (P-1 stage 1)
103
104
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: 67.8
ECM T-Level=1.15 ~= -13-bit
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270
280
Last modified: 2023-04-26T21:34:10+00:00