is 2 1217521 - 1
has 366511 decimal digits
takes 0.037 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
Actual26724.405368.6567 %300000100000000.03684.1690 %24.442169.9634 %
Target2600.126165.0000 %50001500000.00060.8285 %0.126765.2900 %
Difference+7+24.2791+3.6567 %+295000+9850000+0.0363+3.3405%+24.3154+4.6734 %

Known prime factors (2 factors, 139.2 bits, 0.01143104% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
12175213465977127536571548.300142337468
22 × 7 × 13 × 163 × 2399
-16323996.085e-51.267e-51.475e-5
121752122704760947595960825253121192890.875932417631712141343979
3 × 7 × 863 × 1301 × 8069 × 27919 × 175543
2015-01-0527919175543410,955,8140.00160.0025

1 Composite Factors:
P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2015-01-05alpertronManual testing300000100000001222890.8750.0388.292%


Trial Factoring results:
5758596061626364656667
No TF results for M1217521


ECM factoring results:
Total ECM effort:19.135 GHz-days
Estimated T-Level:25.658
DigitsB1CompleteFacMiss
201100014.8080.000%
25500001.62019.795%
302500000.13287.678%
3510000000.00999.129%


ECM Summary

B1B2factorcurvesGHz-days
50000500000028110.73
25000025000000448.402


Lucas-Lehmer results:
No L-L results for M1217521


PRP results:
dateuseridcompidcofactorsres64
2017-09-29Oliver KruseGTX-2
346597712753657
2270476094759596082525312119
9A76CE72A82829A1
2017-10-05Oliver KruseManual testing
346597712753657
2270476094759596082525312119
9A76CE72A82829A1
2017-10-18Oliver KruseThreadripper-PC
346597712753657
2270476094759596082525312119
9A76CE72A82829A1
2018-01-03ATHec2-8x
346597712753657
2270476094759596082525312119
9A76CE72A82829A1


CERT results:
No CERT results for M1217521


P-1 factor-bounds graph:
B1 = 300000, B2 = 10000000 (P-1 stage 2)
B1 = 300000 (P-1 stage 1)
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104
105
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107
TF factor-bounds graph:
this exponent TF target: 60
TF double-checked to: 67
ECM T-Level=25.66 ~= 69-bit
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Last modified: 2024-03-13T02:15:48+00:00