is 2 2020661 - 1
has 608280 decimal digits
takes 0.133 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L977603765C5A01F6double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26829.497769.1176 %40000002000000001.39948.7489 %30.897171.8195 %
Target2620.304066.1290 %80006000000.00381.2734 %0.307966.5603 %
Difference+6+29.1937+2.9886 %+3992000+199400000+1.3956+7.4755%+30.5893+5.2592 %

Known prime factors (1 factor, 89.9 bits, 0.00444762% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
202066111323389498338076933972595032889.871280190232264048173691
3 × 13 × 409 × 17565684425054741
2020-02-294091756568442505474162,044,92991,240,556170,411,950

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2002-04-28Jossv4_computers20002000--0.0000.076%
2002-12-31Mr. P-1v4_computers2500041250012--0.0042.506%
2010-12-08JossManual testing202066202066--0.0192.503%
2013-10-18David Campeaui5-2500k5800001508000012--0.1138.305%
2019-02-25mikrMSI400000020000000012--1.21613.600%


Trial Factoring results:
575859606162636465666768
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
1999-03-26ANONYMOUSv4_computers212580.019
2016-02-23Mark RoseManual testing2582600.057
2009-01-02Sturle Sundefizir.ifi2602610.076
2012-02-04Sebastian HornbostelManual testing2612620.152
2013-02-11dbaughManual testing2622630.486
2015-04-10VictordeHollanderManual testing2632640.972
2015-04-10VictordeHollanderManual testing2642651.849
2015-10-28ramgeisManual testing2652663.698
2016-07-02Gordon SpenceManual testing2662677.396
2019-03-18chuenkitManual testing26726814.79


ECM factoring results:
Total ECM effort:144.610 GHz-days
Estimated T-Level:26.157
DigitsB1CompleteFacMiss
201100013.5870.000%
25500002.12211.981%
302500000.23179.343%
3510000000.02098.050%
4030000000.00199.864%


ECM Summary

B1B2factorcurvesGHz-days
500005000000755.585
50000500000020.147
25000020145066185138.9


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-04-13ANONYMOUSv4_computers977603765C5A01F60.133
2016-07-15Mark Rosemichelangelo977603765C5A01F60.115


PRP results:
dateuseridcompidcofactorsres64
2020-03-01Christoph ZengerManual testing
1132338949833807693397259503
2CB145E40B6A8506
2020-03-03Bommer2600X
1132338949833807693397259503
2CB145E40B6A8506


CERT results:
No CERT results for M2020661


P-1 factor-bounds graph:
B1 = 4000000, B2 = 200000000 (P-1 stage 2)
B1 = 4000000 (P-1 stage 1)
B1 = 580000, B2 = 15080000 (P-1 stage 2)
B1 = 580000 (P-1 stage 1)
B1 = 202066 (P-1 stage 1)
B1 = 25000, B2 = 412500 (P-1 stage 2)
B1 = 25000 (P-1 stage 1)
B1 = 2000 (P-1 stage 1)
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TF factor-bounds graph:
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this exponent TF target: 62
TF double-checked to: 67
ECM T-Level=26.16 ~= 70-bit
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Last modified: 2024-02-29T14:28:04+00:00