is 2 20866421 - 1
has 6281419 decimal digits
takes 14.788 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
Actual2671.424062.6866 %----1.424062.6866 %
Target2695.721563.7681 %150000225000001.40543.7806 %7.126965.1379 %
Difference-2-4.2975-1.0815 %-150000-22500000-1.4054-3.7806 %-5.7029-2.4513 %

Known prime factors (3 factors, 156.1 bits, 0.00074794% known):
Remaining cofactor is PRP status unknown

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
20866421511511097825611445.5401225680
24 × 3 × 5 × 5107
2011-06-191651072.917e-70.00030.0005
208664214553863931320071548.69410911943
7 × 17 × 47 × 1951
2011-06-194719513.401e-60.00020.0002
2086642141105909759652982631961.83498497748511
32 × 35747 × 306157
2016-06-03357473061570.02920.05190.0748

4 Composite Factors:
P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2011-06-19AxonManual testing2994.2340.9410.000%


Trial Factoring results:
57585960616263646566676869
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
2016-06-03TJAOIManual testing261262*
61.834
19
0.012


ECM factoring results:
No ECM results for M20866421


Lucas-Lehmer results:
No L-L results for M20866421


PRP results:
No PRP results for M20866421


CERT results:
No CERT results for M20866421


P-1 factor-bounds graph:
100
101
102
103
104
105
100
101
102
103
104
105
106
TF factor-bounds graph:
this exponent TF target: 69
TF double-checked to: 67
250
260
270
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Last modified: 2024-03-13T02:15:48+00:00