is 2 21757 - 1
has 6550 decimal digits
takes 0.000 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
Actual2671,365.717677.6119 %12000000000360287009607525091,085.820734.6904 %92,451.538385.3785 %
Target2440.000165.9091 %500500000.00001.5991 %0.000166.4542 %
Difference+23+1,365.7175+11.7028 %+11999999500+3602870096025250+91,085.8207+33.0913%+92,451.5381+18.9242 %

Known prime factors (2 factors, 145.9 bits, 0.67046395% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
2175737974786770150969991961.72087270273406607
269 × 324424808203
2014-04-2326932442480820321.5978.201515.318
21757215082825041208731425446472684.153494284195985679853439
7 × 7481 × 1526431 × 6183606607
2009-04-0315264316183606607233,823,2200.15700.2920

1 Composite Factors:
P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2009-07-04GrunwalderGIMPv4_computers2684.153-0.000%
2016-11-18kkmrkkblmbrbkManual testing5000000001000000000012
skipped known factor: 21508282504120873142544647
---42.363%
2023-04-19nordisweet16_30.9b31200000000012000000000
skipped known factor: 21508282504120873142544647
--5.56839.281%
2023-09-29nordisweet16_30.8b14120000000003602870096075250
skipped known factor: 3797478677015096999
skipped known factor: 21508282504120873142544647
--156,79173.412%


P+1 Factoring results:
dateuseridcompidb1b2startfactorSmoothdigitsbits*ghz-days
2021-06-28ATHec2-P_11000000001000000000027--0.316


Trial Factoring results:
5758596061626364656667
No TF results for M21757


ECM factoring results:
Total ECM effort:17.894 GHz-days
Estimated T-Level:35.887
DigitsB1CompleteFacMiss
2011000377.6110.000%
255000076.5650.000%
3025000012.1780.001%
3510000001.60020.199%
4030000000.17783.741%
45110000000.01798.295%
50440000000.00199.854%


ECM Summary

B1B2factorcurvesGHz-days
10.007
50000500000080.002
250000250000009091.513
10000001000000001,3128.760
30000003000000003807.612


Lucas-Lehmer results:
No L-L results for M21757


PRP results:
dateuseridcompidcofactorsres64
2017-09-21Oliver KruseOliver-PC
3797478677015096999
21508282504120873142544647
1F9DBD1B8C133D07
2017-10-02kkmrkkblmbrbkManual testing
3797478677015096999
21508282504120873142544647
1F9DBD1B8C133D07
2017-12-07ATHManual testing
3797478677015096999
21508282504120873142544647
1F9DBD1B8C133D07
2020-04-17Oliver KruseManual testing
3797478677015096999
21508282504120873142544647
18567D662EC4857D


CERT results:
No CERT results for M21757


P-1 factor-bounds graph:
B1 = 12000000000, B2 = 3602870096075250 (P-1 stage 2)
B1 = 12000000000 (P-1 stage 1)
B1 = 500000000, B2 = 10000000000 (P-1 stage 2)
B1 = 500000000 (P-1 stage 1)
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109
1010
1011
101
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109
1010
1011
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1013
1014
1015
1016
TF factor-bounds graph:
this exponent TF target: 44
TF double-checked to: 67
ECM T-Level=35.89 ~= 103-bit
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Last modified: 2024-03-13T02:15:48+00:00