is 2 2156993 - 1
has 649320 decimal digits
takes 0.142 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
Actual26713.775667.1642 %500000150000000.12305.1698 %13.898668.8617 %
Target2620.284864.5161 %100008000000.00511.5188 %0.289965.0551 %
Difference+5+13.4908+2.6481 %+490000+14200000+0.1179+3.6510%+13.6087+3.8067 %

Known prime factors (1 factor, 41.8 bits, 0.00193620% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
215699337336513473371341.764865476
22 × 32 × 29 × 829
-298291.810e-76.920e-68.002e-6

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2016-03-28alpertronManual testing5000001500000012
skipped known factor: 3733651347337
---8.253%


Trial Factoring results:
5758596061626364656667
No TF results for M2156993


ECM factoring results:
Total ECM effort:10.103 GHz-days
Estimated T-Level:21.771
DigitsB1CompleteFacMiss
20110003.7632.320%
25500000.35470.177%
302500000.02397.769%
3510000000.00199.894%


ECM Summary

B1B2factorcurvesGHz-days
500005000000272.305
50000647040770.670
500002702353571.723
543757612500505.404


Lucas-Lehmer results:
No L-L results for M2156993


PRP results:
dateuseridcompidcofactorsres64
2017-10-08Oliver KruseGTX-0
3733651347337
B1B205981D27E84F
2017-11-18kkmrkkblmbrbkc4.xlarge
3733651347337
B1B205981D27E84F


CERT results:
No CERT results for M2156993


P-1 factor-bounds graph:
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
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106
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101
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103
104
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106
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108
TF factor-bounds graph:
this exponent TF target: 62
TF double-checked to: 67
ECM T-Level=21.77 ~= 56-bit
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Last modified: 2024-03-13T02:15:48+00:00