is 2 6978161 - 1
has 2100636 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-LAD32C2E16A56FAC0double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual272137.046768.0556%35000009616446840166.703011.3023%303.749771.6660%
Target2674.258165.6716%4500045000000.09102.2394%4.349166.4404%
Difference+5+132.7885+2.3839%+3455000+9611946840+166.6120+9.0629%+299.4005+5.2256%

Known prime factors:
No known factors for M6978161

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2001-09-16ANONYMOUSv4_computers2500087500---0.009--0.431%
2011-09-07Carsten Kossendeymother44000013530000---0.365--3.520%
2021-11-19Seth_TrManual testing30000007500000012---2.189--5.987%
2023-09-11ThaZ-17035000009616446840---166.7--11.302%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-07-05ANONYMOUSv4_computers21262--0.088--
2001-12-08ANONYMOUSv4_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--4.284--
2020-04-24TJAOIManual testing268269--8.567--
2021-08-09takahashiManual testing269270--17.13--
2021-09-06SRBaseManual testing270271--34.27--
2021-09-25SRBaseManual testing271272--68.54--


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)
1999-03-26WanderingShoev4_computersAD32C2E16A56FAC01.522
2002-02-03ANONYMOUSv4_computersAD32C2E16A56FAC01.522


PRP results:
No PRP results for M6978161


P-1 factor-bounds graph:
B1 = 3500000, B2 = 9616446840 (P-1 stage 2)
B1 = 3000000, B2 = 75000000 (P-1 stage 2)
B1 = 3500000 (P-1 stage 1)
B1 = 3000000 (P-1 stage 1)
B1 = 440000, B2 = 13530000 (P-1 stage 2)
B1 = 440000 (P-1 stage 1)
B1 = 25000, B2 = 87500 (P-1 stage 2)
B1 = 25000 (P-1 stage 1)
103
104
105
106
107
103
104
105
106
107
108
109
1010
TF factor-bounds graph:
272
271
270
269
268
267
266
265
264
263
262
this exponent TF target: 67
TF double-checked to: 67.9
ECM T-Level=1.15 ~= -13-bit
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Last modified: 2023-10-02T12:12:48+00:00