is 2 2817421 - 1
has 848129 decimal digits
takes 0.218 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L9973D37151A97C6Edouble-checked
PRP6D7D742CE64E1A54verified PRP

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26942.374568.1159%50000002000000001.74988.4859%44.124370.8216%2.7056%
PrimeNet2590.027362.7119%120002400000.00272.9304%0.030063.8046%1.0927%
GPU722630.566565.0794%150002600000.00321.7918%0.569765.7051%0.6257%
Difference+6+41.8080+3.0366%+4985000+199740000+1.7466+6.6940%+43.5546+5.1165%+5.1165%

Known prime factors (1 factor, 79.1 bits, 0.00280891% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
28174216655476498527806739701432479.139118112921329964651
23 × 179 × 28689074891903
2021-06-061792868907489190353,718175,051326,946

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-11-28T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.196%
2016-09-13T03:53:09Jocelyn Larouchelow 4M13505933000006---0.034--2.612%
2016-09-21T12:09:26Jocelyn Larouchelow 4M1350593630000---0.036--2.668%
2016-12-21T00:33:39Jocelyn Larouchelow 4M194484194484---0.022--1.064%
2017-01-10T10:25:18Jocelyn Larouchelow 4M233380233380---0.026--1.170%
2017-03-17T00:52:41Jocelyn Larouchelow 4M33606733606706---0.056--3.028%
2018-09-03T21:22:26Jocelyn Larouchelow 4M499280499280---0.056--1.681%
2019-10-03T23:34:06masserManual testing28174212817421012---0.470--5.851%
2020-01-15T14:04:59masserManual testing500000020000000012---1.750--8.486%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-07-29T00:00:00ANONYMOUSv4_computers21259--0.027--
2016-02-23T16:29:22Mark RoseManual testing259260--0.027--
2009-02-12T05:19:00Sturle Sundefizir.ifi260261--0.055--
2012-02-21T14:24:00Grant McCrackenthumper261262--0.109--
2013-01-10T10:21:00dbaughManual testing262263--0.348--
2015-04-21T09:19:00VictordeHollanderManual testing263264--0.697--
2015-04-21T09:19:00VictordeHollanderManual testing264265--1.326--
2016-02-12T10:12:10ramgeisManual testing265266--2.652--
2017-10-24T17:48:50Gordon SpenceManual testing266267--5.305--
2019-01-01T23:16:49chuenkitManual testing267268--10.61--
2021-05-19T10:49:46TJAOIManual testing268269--21.22--


ECM factoring results:

Old Calculation Method

Total ECM effort:8.552 GHz-days
Estimated T-Level:4.100
DigitsB1CurvesCompleteFacMiss
201100082 / 1000.82043.862%
255000082 / 2800.29374.574%

New Calculation Method

Total ECM effort:8.552 GHz-days
Estimated T-Level:4.100
DigitsB1CompleteFacMiss
20110003.1544.269%
25500000.29274.691%
302500000.01898.176%


ECM Summary

B1B2factorcurvesGHz-days
500005000000798.239
50000500000030.313


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1998-07-29T00:00:00ANONYMOUSv4_computers9973D37151A97C6E0.218
1999-05-02T00:00:00ANONYMOUSv4_computers9973D37151A97C6E0.218
2018-09-06T01:43:38kkmrkkblmbrbkold9973D37151A97C6E0.218


PRP results:
dateuseridcompidcofactorsres64PRP
2021-06-07T14:50:35tottenhoff2018pc
665547649852780673970143
6D7D742CE64E1A54no


P-1 factor-bounds graph:
B1 = 5000000, B2 = 200000000 (P-1 stage 2)
B1 = 5000000 (P-1 stage 1)
B1 = 2817421, B2 = 28174210 (P-1 stage 2)
B1 = 2817421 (P-1 stage 1)
B1 = 336067, B2 = 3360670 (P-1 stage 2)
B1 = 499280 (P-1 stage 1)
B1 = 336067 (P-1 stage 1)
B1 = 135059, B2 = 3630000 (P-1 stage 2)
B1 = 135059, B2 = 3300000 (P-1 stage 2)
B1 = 233380 (P-1 stage 1)
B1 = 194484 (P-1 stage 1)
B1 = 135059 (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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Last modified: 2021-06-07T14:50:35+00:00