is 2 1621861 - 1
has 488229 decimal digits
takes 0.072 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LBC3AEE873D158B57double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26718.320968.6567%1000000200000000.13185.6766%18.452770.4360%1.7792%
PrimeNet2570.011863.1579%70001200000.00092.5549%0.012764.0992%0.9413%
GPU722610.189465.5738%6500600000.00061.0595%0.190065.9385%0.3648%
Difference+6+18.1315+3.0829%+993500+19940000+0.1312+4.6171%+18.2627+4.4974%+4.4974%

Known prime factors (1 factor, 76.0 bits, 0.00468582% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
1621861754253878678744359887772375.99723252728768949508
22 × 3 × 29 × 66818186117671
2016-03-2629668181861176716,115.0235,779440,370

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2004-02-07T00:00:00markrv4_computers20000310000---0.002--1.023%
2011-11-29T13:51:00BigBrotherWinston100000020000000---0.132--5.677%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-11-07T00:00:00ANONYMOUSv4_computers21257--0.012--
2003-07-06T00:00:00ANONYMOUSv4_computers21258--0.024--
2016-02-23T16:28:41Mark RoseManual testing258260--0.071--
2010-05-03T21:50:00Architects Cubeda3_lm260261--0.095--
2016-02-23T16:28:41Mark RoseManual testing261262--0.189--
2010-08-13T02:23:00GrunwalderGIMPManual testing21263--0.984--
2016-02-23T16:28:41Mark RoseManual testing262263--0.605--
2015-04-29T10:57:00omylistManual testing263264--1.211--
2015-04-30T14:35:00monstManual testing264265--2.304--
2015-10-11T16:52:46ramgeisManual testing265266--4.608--


ECM factoring results:

Old Calculation Method

Total ECM effort:14.092 GHz-days
Estimated T-Level:24.482
DigitsB1CurvesCompleteFacMiss
2011000251 / 1002.5108.025%
2550000251 / 2800.89640.737%

New Calculation Method

Total ECM effort:14.092 GHz-days
Estimated T-Level:24.482
DigitsB1CompleteFacMiss
20110008.0970.030%
25500000.73248.105%
302500000.04595.594%
3510000000.00299.794%


ECM Summary

B1B2factorcurvesGHz-days
50000500000024913.98
50000500000020.112


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1998-11-14T00:00:00ANONYMOUSv4_computersBC3AEE873D158B570.072
2015-07-19T18:02:00MadPooManual testingBC3AEE873D158B570.072


PRP results:
dateuseridcompidcofactorsres64PRP
2017-10-02T14:20:31Oliver KruseGTX-2
75425387867874435988777
1DECA73053D4C4__no
2017-11-01T14:26:58kkmrkkblmbrbkc4.xlarge
75425387867874435988777
1DECA73053D4C4__no


P-1 factor-bounds graph:
B1 = 1000000, B2 = 20000000 (P-1 stage 2)
B1 = 1000000 (P-1 stage 1)
B1 = 20000, B2 = 310000 (P-1 stage 2)
B1 = 20000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2019-10-28T14:12:36+00:00