is 2 2155291 - 1
has 648808 decimal digits
takes 0.142 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LF4D2CFC799C31FBEdouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26827.655167.6471%25000001250000000.87467.9188%28.529870.2090%2.5620%
PrimeNet2580.017862.0690%100001700000.00182.8091%0.019663.1345%1.0655%
GPU722620.285064.5161%100001600000.00171.5186%0.286865.0550%0.5388%
Difference+6+27.3701+3.1309%+2490000+124840000+0.8729+6.4003%+28.2430+5.1541%+5.1541%

Known prime factors (1 factor, 74.2 bits, 0.00344397% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
2155291221175094234537626010012374.2285130979859205500
22 × 53 × 449 × 22855144139
2020-07-17449228551441393,073.8118.72221.73

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-03-07T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.225%
2010-11-03T21:25:00Jocelyn LaroucheManual testing2000020000---0.002--0.255%
2010-12-30T22:20:00Jocelyn LaroucheManual testing3000030000---0.003--0.353%
2011-01-15T02:57:00Jocelyn LaroucheManual testing5000050000---0.005--0.513%
2011-01-24T09:50:00markrtiny1200002340000---0.023--2.545%
2014-10-01T22:53:00Jocelyn LaroucheManual testing149780149780---0.014--1.008%
2016-03-22T02:16:49Jocelyn LaroucheManual testing269604269604---0.026--1.367%
2016-04-09T18:54:43Jocelyn LaroucheManual testing360000648000012---0.066--3.802%
2017-12-29T16:48:02mikrMSI250000012500000012---0.875--7.919%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-02-07T00:00:00ANONYMOUSv4_computers21258--0.018--
2016-02-23T16:29:07Mark RoseManual testing258260--0.053--
2009-01-04T22:11:00Sturle Sundegigi.ifi260261--0.071--
2009-01-07T16:23:00Sturle Sunderodolfo.ifi261262--0.143--
2013-09-08T17:50:00ramgeisManual testing262263--0.455--
2015-03-22T08:28:00VictordeHollanderManual testing263264--0.911--
2015-03-22T08:28:00VictordeHollanderManual testing264265--1.734--
2015-12-30T18:01:34ramgeisManual testing265266--3.467--
2016-11-04T03:09:03Gordon SpenceManual testing266267--6.934--
2019-05-20T13:24:29TJAOIManual testing267268--13.87--


ECM factoring results:

Old Calculation Method

Total ECM effort:8.367 GHz-days
Estimated T-Level:4.900
DigitsB1CurvesCompleteFacMiss
201100098 / 1000.98037.346%
255000098 / 2800.35070.425%

New Calculation Method

Total ECM effort:8.367 GHz-days
Estimated T-Level:4.900
DigitsB1CompleteFacMiss
20110003.1614.237%
25500000.28675.148%
302500000.01898.256%


ECM Summary

B1B2factorcurvesGHz-days
500005000000968.196
50000500000020.171


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-02-14T00:00:00ANONYMOUSv4_computersF4D2CFC799C31FBE0.142
1999-07-30T00:00:00ANONYMOUSv4_computersF4D2CFC799C31FBE0.142
1999-08-31T00:00:00ANONYMOUSv4_computersF4D2CFC799C31FBE0.142


PRP results:
dateuseridcompidcofactorsres64PRP
2020-07-17T13:13:44CrypticClueManual testing
22117509423453762601001
5D2E141865836364no
2020-07-17T15:12:01oodairacom2
22117509423453762601001
5D2E141865836364no


P-1 factor-bounds graph:
B1 = 2500000, B2 = 125000000 (P-1 stage 2)
B1 = 2500000 (P-1 stage 1)
B1 = 360000, B2 = 6480000 (P-1 stage 2)
B1 = 360000 (P-1 stage 1)
B1 = 269604 (P-1 stage 1)
B1 = 120000, B2 = 2340000 (P-1 stage 2)
B1 = 149780 (P-1 stage 1)
B1 = 120000 (P-1 stage 1)
B1 = 50000 (P-1 stage 1)
B1 = 30000 (P-1 stage 1)
B1 = 20000 (P-1 stage 1)
B1 = 2048, B2 = 204800 (P-1 stage 2)
B1 = 2048 (P-1 stage 1)
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TF factor-bounds graph:
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265
264
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2100
Last modified: 2020-07-17T15:12:01+00:00