is 2 1639987 - 1
has 493686 decimal digits
takes 0.073 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L11C2CA72EB1832B1double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26718.118468.6567 %500000150000000.08355.0020 %18.201970.2245 %
Target2610.187365.5738 %65003500000.00161.1198 %0.188965.9593 %
Difference+6+17.9311+3.0829 %+493500+14650000+0.0819+3.8822%+18.0130+4.2652 %

Known prime factors (1 factor, 62.9 bits, 0.00383576% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
163998786415069210615858491962.9062634626652852
22 × 3 × 46633 × 4708087
2008-05-214663347080870.37460.01950.0310

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2016-03-17alpertronManual testing5000001500000012
skipped known factor: 8641506921061585849
---8.760%


Trial Factoring results:
5758596061626364656667
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
1998-11-07ANONYMOUSv4_computers212570.012
2003-06-06ANONYMOUSv4_computers212580.023
2003-06-17ANONYMOUSv4_computers212580.023


ECM factoring results:
Total ECM effort:31.425 GHz-days
Estimated T-Level:25.716
DigitsB1CompleteFacMiss
201100014.5770.000%
25500001.66718.874%
302500000.14386.662%
3510000000.01099.007%


ECM Summary

B1B2factorcurvesGHz-days
10.085
50000500000024914.00
250000400000005017.35


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1998-11-07ANONYMOUSv4_computers11C2CA72EB1832B10.073


PRP results:
dateuseridcompidcofactorsres64
2017-10-02Oliver KruseGTX-0
8641506921061585849
E37D460754DE1FC2
2017-11-02kkmrkkblmbrbkc4.xlarge
8641506921061585849
E37D460754DE1FC2


CERT results:
No CERT results for M1639987


P-1 factor-bounds graph:
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
103
104
105
106
103
104
105
106
107
108
TF factor-bounds graph:
258
257
this exponent TF target: 61
TF double-checked to: 67
ECM T-Level=25.72 ~= 69-bit
250
260
270
JSON version of this page
Last modified: 2024-02-09T03:30:02+00:00