is 2 193871 - 1
has 58361 decimal digits
takes 0.001 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
Actual267153.266473.1343 %10000000020000000001.360712.3031 %154.627276.4396 %
Target2440.000059.0909 %36004000000.00028.8196 %0.000262.6989 %
Difference+23+153.2664+14.0434 %+99996400+1999600000+1.3606+3.4834%+154.6270+13.7407 %

Known prime factors (2 factors, 96.1 bits, 0.04956871% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
193871387743618.5651
1
-111.801e-136.686e-91.361e-8
1938712188987152571858265938812477.535564547341420805140
22 × 32 × 5 × 19 × 157 × 5051 × 208159981
2015-05-295051208159981157,8790.07590.1416

1 Composite Factors:
P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2017-08-23kkmrkkblmbrbkManual testing100000000200000000012
skipped known factor: 387743
skipped known factor: 218898715257185826593881
---41.988%


P+1 Factoring results:
dateuseridcompidb1b2startfactorSmoothdigitsbits*ghz-days
2021-07-11ATHec2-P_115000000150000000027--0.586


Trial Factoring results:
5758596061626364656667
No TF results for M193871


ECM factoring results:
Total ECM effort:13.487 GHz-days
Estimated T-Level:29.323
DigitsB1CompleteFacMiss
201100057.7300.000%
25500008.2400.026%
302500000.86542.125%
3510000000.07193.149%
4030000000.00599.527%


ECM Summary

B1B2factorcurvesGHz-days
5000050000002611.273
500005000000200.098
250000250000003889.016
25000035750000982.342
2500003600000070.195
2500003725000070.198
2500009859290020.096
25000036755218520.269


Lucas-Lehmer results:
No L-L results for M193871


PRP results:
dateuseridcompidcofactorsres64
2017-09-22Oliver KruseOllaptop
387743
218898715257185826593881
7020B2DD6CE95768
2017-09-22Oliver KruseManual testing
387743
218898715257185826593881
7020B2DD6CE95768
2017-10-12kkmrkkblmbrbkc4.xlarge
387743
218898715257185826593881
7020B2DD6CE95768
2020-04-17Oliver KruseAddPrpType5
387743
218898715257185826593881
D781041917F92889
2022-05-12Jorge CoveiroManual testing
387743
D781041917F92889
2023-08-24USAFSS6917th_Scty_Sq
387743
218898715257185826593881
D781041917F92889


CERT results:
dateuseridcompid
2023-08-24LOBESRD_EVO


P-1 factor-bounds graph:
B1 = 100000000, B2 = 2000000000 (P-1 stage 2)
B1 = 100000000 (P-1 stage 1)
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109
1010
TF factor-bounds graph:
this exponent TF target: 44
TF double-checked to: 67
ECM T-Level=29.32 ~= 81-bit
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Last modified: 2024-03-13T02:15:48+00:00