is 2 20807 - 1
has 6264 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-L9F4D7F7A42ADC667double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual2671,428.073177.6119%25000000000250024693185267063,217.210434.7218%64,645.283685.3855%7.7735%
PrimeNet2400.000062.5000%500100000.00003.7346%0.000063.9005%1.4005%
GPU722440.000165.9091%500100000.00001.5779%0.000166.4470%0.5379%
Difference+23+1,428.0730+11.7028%+24999999500+2500246931842670+63,217.2104+33.1438%+64,645.2835+18.9385%+18.9385%

Known prime factors:
No known factors for M20807

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2001-04-29T00:00:00ANONYMOUSv4_computers10000010000000---0.000--1.839%
2001-08-18T00:00:00Alex Kruppav4_computers1000000100000000---0.003--4.555%
2002-04-28T00:00:00ANONYMOUSv4_computers163841638400---4.86067e-5--0.603%
2002-06-09T00:00:00ANONYMOUSv4_computers327683276800---9.72135e-5--0.979%
2002-07-20T00:00:00ANONYMOUSv4_computers655366553600---0.000--1.476%
2003-02-02T00:00:00ANONYMOUSv4_computers13107213107200---0.000--2.096%
2003-03-27T00:00:00ANONYMOUSv4_computers26214426214400---0.001--2.833%
2003-04-03T00:00:00ANONYMOUSv4_computers52428852428800---0.002--3.679%
2003-04-27T00:00:00ANONYMOUSv4_computers1048576104857600---0.003--4.623%
2003-05-19T00:00:00ANONYMOUSv4_computers2097152209715200---0.006--5.659%
2003-07-06T00:00:00ANONYMOUSv4_computers4194304419430400---0.012--6.780%
2003-09-29T00:00:00ANONYMOUSv4_computers8388608838860800---0.025--7.981%
2003-09-29T00:00:00ANONYMOUSv4_computers167772161677721600---0.050--9.248%
2006-02-15T00:00:00Jocelyn Larouchev4_computers100000000100000000---0.046--6.070%
2013-02-22T00:18:00bcp19Toshiba-740Q10000000000100000000000---6.915--17.808%
2021-12-24T12:13:47Stef42Manual testing10000000000750656704147350---18,981--32.281%
2022-06-05T23:11:09ATHManual testing250000000002500246931852670---63,217--34.722%


P+1 Factoring results:
dateuseridcompidb1b2startfactorSmoothdigitsbits*ghz-days
2021-05-08T04:17:16ATH5960X50000000010150000000027--2.855


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-10-15T00:00:00ANONYMOUSv4_computers252253--0.029--
2000-03-01T00:00:00ANONYMOUSv4_computers253254--0.058--
2000-08-31T00:00:00ANONYMOUSv4_computers21256--0.461--
2002-11-02T00:00:00ANONYMOUSv4_computers21257--0.923--
2016-02-23T04:51:21LaurVManual testing257258--0.923--
2009-01-10T00:17:00Sturle Sundegigotte.ifi258259--1.845--
2009-01-30T15:02:00Sturle Sundeniemeyer.ifi259260--3.691--
2011-06-12T03:16:00Richard B. WoodsPuttputt260261--7.382--
2012-08-25T13:38:00bcp19Manual testing261262--14.76--
2016-09-14T05:50:28Sid & AndyMrs_Potato_Head262263--47.18--
2018-01-24T16:30:05YxinityManual testing263264--94.36--
2018-01-20T19:43:51YxinityYGSMainFrame263264--94.36--
2018-10-04T05:30:19YxinityManual testing264265--179.6--
2018-10-03T16:29:01YxinityYGSMainFrame264265--179.6--
2020-01-03T13:21:47YxinityManual testing265266--359.1--


ECM factoring results:

Old Calculation Method

Total ECM effort:2,837.125 GHz-days
Estimated T-Level:45.060
DigitsB1CurvesCompleteFacMiss
201100011673 / 100116.7300.000%
255000011673 / 28041.6890.000%
3025000011673 / 64018.2390.000%
35100000011600 / 15667.4070.061%
40300000010545 / 45882.29810.040%
45110000009272 / 92011.00836.503%
5044000000200 / 165500.01298.799%

New Calculation Method

Total ECM effort:2,837.125 GHz-days
Estimated T-Level:45.060
DigitsB1CompleteFacMiss
20110003,032.7970.000%
25500001,023.4150.000%
30250000253.5250.000%
35100000051.6310.000%
4030000009.0350.012%
45110000001.38025.145%
50440000000.18882.822%
551100000000.02397.687%
602600000000.00399.734%


ECM Summary

B1B2factorcurvesGHz-days
25000025000000700.117
10000001000000001,0557.044
30000003000000001,27325.50
110000001100000030.149
1100000011000000008,028589.6
1100000035133391030760617.6
430000002404906604262841,538
44000000440000000020058.76


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
2015-04-11T05:57:00MadPooManual testing9F4D7F7A42ADC6676.65824e-6


PRP results:
No PRP results for M20807


P-1 factor-bounds graph:
B1 = 25000000000, B2 = 2500246931852670 (P-1 stage 2)
B1 = 10000000000, B2 = 750656704147350 (P-1 stage 2)
B1 = 25000000000 (P-1 stage 1)
B1 = 10000000000, B2 = 100000000000 (P-1 stage 2)
B1 = 10000000000 (P-1 stage 1)
B1 = 16777216, B2 = 1677721600 (P-1 stage 2)
B1 = 100000000 (P-1 stage 1)
B1 = 8388608, B2 = 838860800 (P-1 stage 2)
B1 = 4194304, B2 = 419430400 (P-1 stage 2)
B1 = 16777216 (P-1 stage 1)
B1 = 2097152, B2 = 209715200 (P-1 stage 2)
B1 = 8388608 (P-1 stage 1)
B1 = 1048576, B2 = 104857600 (P-1 stage 2)
B1 = 1000000, B2 = 100000000 (P-1 stage 2)
B1 = 4194304 (P-1 stage 1)
B1 = 524288, B2 = 52428800 (P-1 stage 2)
B1 = 2097152 (P-1 stage 1)
B1 = 262144, B2 = 26214400 (P-1 stage 2)
B1 = 1048576 (P-1 stage 1)
B1 = 1000000 (P-1 stage 1)
B1 = 131072, B2 = 13107200 (P-1 stage 2)
B1 = 100000, B2 = 10000000 (P-1 stage 2)
B1 = 524288 (P-1 stage 1)
B1 = 65536, B2 = 6553600 (P-1 stage 2)
B1 = 262144 (P-1 stage 1)
B1 = 32768, B2 = 3276800 (P-1 stage 2)
B1 = 131072 (P-1 stage 1)
B1 = 16384, B2 = 1638400 (P-1 stage 2)
B1 = 100000 (P-1 stage 1)
B1 = 65536 (P-1 stage 1)
B1 = 32768 (P-1 stage 1)
B1 = 16384 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2022-06-05T23:11:09+00:00