is 2 2491681 - 1
has 750071 decimal digits
takes 0.173 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L51D67B64CB1BC5FAdouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26711.925267.1642 %2000000600000000.51907.6446 %12.444269.6743 %
Target2630.640565.0794 %110008000000.00541.3811 %0.646065.5617 %
Difference+4+11.2847+2.0848 %+1989000+59200000+0.5135+6.2634%+11.7982+4.1127 %

Known prime factors (1 factor, 67.1 bits, 0.00269217% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
24916811560200209199353733532167.08031308185301396
22 × 3 × 37 × 70513930859
2013-08-29377051393085911.925386.38721.66

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2003-10-23ANONYMOUSv4_computers2048204800--0.0010.661%
2003-10-31Team Prime Ribv4_computers15000228750--0.0031.688%
2010-12-22JossManual testing2000020000--0.0020.621%
2011-01-22Oscar Östlin9500019475006--0.0204.245%
2019-07-04alpertronManual testing20000006000000012---10.561%


Trial Factoring results:
5758596061626364656667
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
1999-05-02ANONYMOUSv4_computers212590.015
2022-03-10LordJuliusManual testing21260
2009-01-16Sturle Sundevancraft.ifi2602610.062
2012-06-11Sebastian HornbostelManual testing2612620.123


ECM factoring results:
Total ECM effort:0.789 GHz-days
Estimated T-Level:1.538
DigitsB1CompleteFacMiss
20110000.30873.514%
25500000.02897.193%
302500000.00299.821%


ECM Summary

B1B2factorcurvesGHz-days
10.184
50000500000080.605


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-05-16ANONYMOUSv4_computers51D67B64CB1BC5FA0.173


PRP results:
dateuseridcompidcofactorsres64
2017-10-14kkmrkkblmbrbkc4.xlarge
156020020919935373353
23241B6C29786B02
2017-11-06Oliver KruseGTX-3
156020020919935373353
23241B6C29786B02


CERT results:
No CERT results for M2491681


P-1 factor-bounds graph:
B1 = 2000000, B2 = 60000000 (P-1 stage 2)
B1 = 2000000 (P-1 stage 1)
B1 = 95000, B2 = 1947500 (P-1 stage 2)
B1 = 95000 (P-1 stage 1)
B1 = 15000, B2 = 228750 (P-1 stage 2)
B1 = 20000 (P-1 stage 1)
B1 = 15000 (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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this exponent TF target: 63
TF double-checked to: 67
ECM T-Level=1.54 ~= -11-bit
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Last modified: 2024-02-09T03:30:02+00:00