is 2 2156897 - 1
has 649291 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-LE5A82D4AC56F4C38double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26955.351268.1159 %5000000989699403051.858213.0599 %107.209472.2800 %
Target2620.284864.5161 %100008000000.00511.5188 %0.289965.0551 %
Difference+7+55.0663+3.5998 %+4990000+9896194030+51.8531+11.5411%+106.9195+7.2249 %

Known prime factors:
No known factors for M2156897

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2003-03-07ANONYMOUSv4_computers204820480012--0.0010.775%
2010-11-04JossManual testing1500015000--0.0010.577%
2010-11-07JossManual testing3000030000--0.0030.934%
2010-11-07JossManual testing4500045000--0.0041.196%
2010-11-10JossManual testing6000060000--0.0061.408%
2011-01-24markrtiny12000023400006--0.0234.990%
2014-10-03JossManual testing149758149758--0.0142.218%
2016-04-16JossManual testing240000884298012--0.0687.010%
2017-09-13JossManual testing48000048000006---6.661%
2017-09-19JossManual testing57600057600006--0.0827.003%
2019-09-26mikrMSI400000020000000012--1.39913.672%
2021-06-24Dylan Delgadolaptop-ryzen737004800000676800000--3.94815.846%
2023-01-04Architects Cubedgpu7250000009896994030--54.7120.227%


Trial Factoring results:
57585960616263646566676869
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
1999-01-29Martijn Ottov4_computers212580.018
2016-02-23Mark RoseManual testing2582600.053
2009-01-04Sturle Sundejodel.ifi2602610.071
2009-01-07Sturle Sundemorovan.ifi2612620.142
2013-09-08ramgeisManual testing2622630.455
2015-03-22VictordeHollanderManual testing2632652.643
2015-12-30ramgeisManual testing2652663.465
2016-11-03Gordon SpenceManual testing2662676.929
2019-05-13TJAOIManual testing26726813.86
2021-07-29TJAOIManual testing26826927.72


ECM factoring results:
Total ECM effort:17.443 GHz-days
Estimated T-Level:23.641
DigitsB1CompleteFacMiss
20110007.8580.039%
25500000.72848.276%
302500000.04695.499%
3510000000.00299.784%


ECM Summary

B1B2factorcurvesGHz-days
50000500000019516.51
50000675000070.683
766202417689010.246


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-02-07Martijn Ottov4_computersE5A82D4AC56F4C380.142
2018-04-10kkmrkkblmbrbkoldE5A82D4AC56F4C380.142


PRP results:
No PRP results for M2156897


CERT results:
No CERT results for M2156897


P-1 factor-bounds graph:
B1 = 5000000, B2 = 9896994030 (P-1 stage 2)
B1 = 4800000, B2 = 676800000 (P-1 stage 2)
B1 = 4000000, B2 = 200000000 (P-1 stage 2)
B1 = 5000000 (P-1 stage 1)
B1 = 4800000 (P-1 stage 1)
B1 = 4000000 (P-1 stage 1)
B1 = 576000, B2 = 5760000 (P-1 stage 2)
B1 = 480000, B2 = 4800000 (P-1 stage 2)
B1 = 240000, B2 = 8842980 (P-1 stage 2)
B1 = 576000 (P-1 stage 1)
B1 = 480000 (P-1 stage 1)
B1 = 120000, B2 = 2340000 (P-1 stage 2)
B1 = 240000 (P-1 stage 1)
B1 = 149758 (P-1 stage 1)
B1 = 120000 (P-1 stage 1)
B1 = 60000 (P-1 stage 1)
B1 = 45000 (P-1 stage 1)
B1 = 30000 (P-1 stage 1)
B1 = 15000 (P-1 stage 1)
B1 = 2048, B2 = 204800 (P-1 stage 2)
B1 = 2048 (P-1 stage 1)
102
103
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105
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102
103
104
105
106
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109
1010
TF factor-bounds graph:
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268
267
266
265
263
262
261
260
258
this exponent TF target: 62
TF double-checked to: 67
ECM T-Level=23.64 ~= 62-bit
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Last modified: 2024-03-13T02:15:48+00:00