is 2 1666853 - 1
has 501773 decimal digits
takes 0.078 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L-unknown--unknown-
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26717.826468.6567 %500000150000000.08805.0118 %17.914470.2276 %
Target2610.184365.5738 %70004000000.00191.2063 %0.186265.9890 %
Difference+6+17.6421+3.0829 %+493000+14600000+0.0861+3.8056%+17.7282+4.2385 %

Known prime factors (2 factors, 51.2 bits, 0.00306987% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
166685310001119823.2543
3
-136.709e-137.568e-81.389e-7
1666853253361657927.91776
22 × 19
2008-07-154191.090e-113.287e-75.555e-7

1 Composite Factors:
P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2016-03-17alpertronManual testing5000001500000012
skipped known factor: 10001119
skipped known factor: 253361657
---8.776%


Trial Factoring results:
5758596061626364656667
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
2008-07-15J FeitsmaManual testing??
27.917
9


ECM factoring results:
Total ECM effort:38.221 GHz-days
Estimated T-Level:25.718
DigitsB1CompleteFacMiss
201100014.6540.000%
25500001.67418.740%
302500000.14486.623%
3510000000.01099.005%


ECM Summary

B1B2factorcurvesGHz-days
50000500000025117.11
250000400000005021.11


Lucas-Lehmer results:
No L-L results for M1666853


PRP results:
dateuseridcompidcofactorsres64
2017-10-02Oliver KruseGTX-2
10001119
253361657
6B3039388370BA08
2017-11-02kkmrkkblmbrbkold
10001119
253361657
6B3039388370BA08


CERT results:
No CERT results for M1666853


P-1 factor-bounds graph:
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
100
101
102
103
104
105
106
100
101
102
103
104
105
106
107
108
TF factor-bounds graph:
this exponent TF target: 61
TF double-checked to: 67
ECM T-Level=25.72 ~= 69-bit
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270
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Last modified: 2024-03-13T02:15:48+00:00