is 2 172871 - 1
has 52040 decimal digits
takes 0.001 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LCF0248613EEC9DE9double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual267171.884973.1343%10000000020000000001.360712.2015%173.245776.4123%3.2780%
PrimeNet2400.000055.0000%1900400000.000011.5847%0.000060.2131%5.2131%
GPU722440.000059.0909%3200650000.00008.0949%0.000162.4024%3.3115%
Difference+23+171.8849+14.0434%+99996800+1999935000+1.3607+4.1066%+173.2456+14.0099%+14.0099%

Known prime factors (1 factor, 81.5 bits, 0.04711965% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
17287133171377717370773340098632581.4569594257486036053861
157 × 181 × 1163 × 1559 × 186211849
2009-01-2115591862118493,937,2970.06780.1267

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2001-05-06T00:00:00ANONYMOUSv4_computers10000010000000---0.004--2.564%
2002-06-02T00:00:00ANONYMOUSv4_computers327683276800---0.001--1.452%
2002-07-27T00:00:00ANONYMOUSv4_computers655366553600---0.003--2.103%
2003-02-09T00:00:00ANONYMOUSv4_computers13107213107200---0.006--2.883%
2003-10-08T00:00:00ANONYMOUSv4_computers26214426214400---0.011--3.779%
2017-05-07T09:01:59kkmrkkblmbrbkManual testing100000000200000000012-
skipped known factor: 3317137771737077334009863
--1.361--12.201%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-11-10T00:00:00ANONYMOUSv4_computers252253--0.003--
2000-04-27T00:00:00ANONYMOUSv4_computers21254--0.014--
2022-03-07T04:17:12LordJuliusManual testing254255--0.014--
2001-01-21T00:00:00ANONYMOUSv4_computers21256--0.056--
2002-06-02T00:00:00ANONYMOUSv4_computers21257--0.111--
2022-03-07T04:17:12LordJuliusManual testing257258--0.111--
2008-12-30T10:58:00Sturle Sundehummel.ifi258259--0.222--


ECM factoring results:

Old Calculation Method

Total ECM effort:15.193 GHz-days
Estimated T-Level:29.445
DigitsB1CurvesCompleteFacMiss
2011000848 / 1008.4800.020%
2550000848 / 2803.0294.812%
30250000569 / 6400.88941.076%

New Calculation Method

Total ECM effort:15.193 GHz-days
Estimated T-Level:29.445
DigitsB1CompleteFacMiss
201100062.4580.000%
25500009.0070.012%
302500000.94838.769%
3510000000.07892.507%
4030000000.00599.480%


ECM Summary

B1B2factorcurvesGHz-days
10.00000e+0
5000050000002791.357
2500002500000056913.84


Lucas-Lehmer results:
No L-L results for M172871


PRP results:
dateuseridcompidcofactorsres64PRP
2017-09-22T00:17:22Oliver KruseDoppelherz
3317137771737077334009863
F20B09262D26C6__no
2017-09-22T10:02:00Oliver KruseManual testing
3317137771737077334009863
F20B09262D26C6__no
2017-10-12T01:37:31kkmrkkblmbrbkc4.xlargeF20B09262D26C6__no
2020-04-17T17:53:56Oliver KruseAddPrpType5
3317137771737077334009863
55A9CC9D228D88__no


P-1 factor-bounds graph:
B1 = 100000000, B2 = 2000000000 (P-1 stage 2)
B1 = 100000000 (P-1 stage 1)
B1 = 262144, B2 = 26214400 (P-1 stage 2)
B1 = 131072, B2 = 13107200 (P-1 stage 2)
B1 = 100000, B2 = 10000000 (P-1 stage 2)
B1 = 65536, B2 = 6553600 (P-1 stage 2)
B1 = 262144 (P-1 stage 1)
B1 = 32768, B2 = 3276800 (P-1 stage 2)
B1 = 131072 (P-1 stage 1)
B1 = 100000 (P-1 stage 1)
B1 = 65536 (P-1 stage 1)
B1 = 32768 (P-1 stage 1)
102
103
104
105
106
107
108
102
103
104
105
106
107
108
109
1010
TF factor-bounds graph:
267
259
258
257
256
255
254
253
250
260
270
280
290
2100
Last modified: 2022-03-07T04:17:12+00:00