is 2 1521757 - 1
has 458095 decimal digits
takes 0.068 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L0684C70F9D7C526Adouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26839.168569.1176%100000002000000001.31819.0186%40.486671.9028%2.7852%
PrimeNet2570.012663.1579%65001100000.00082.4117%0.013464.0464%0.8885%
GPU722610.201965.5738%6500550000.00061.0130%0.202565.9225%0.3487%
Difference+7+38.9666+3.5439%+9993500+199945000+1.3175+8.0056%+40.2841+5.9803%+5.9803%

Known prime factors:
No known factors for M1521757

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2011-01-29T11:32:00James HeinrichWHS800001340000---0.010--1.935%
2013-11-21T23:21:00David Campeaui5-2500k94500027405000---0.155--5.416%
2015-02-24T22:12:00VictordeHollanderManual testing10000000200000000---1.318--9.019%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1997-11-12T00:00:00ANONYMOUSv4_computers21256--0.006--
1998-12-27T00:00:00Lars Lindleyv4_computers21257--0.013--
2003-08-08T00:00:00ANONYMOUSv4_computers21258--0.025--
2016-02-23T16:28:36Mark RoseManual testing258260--0.076--
2010-04-25T11:30:00Architects Cubeda3_bu2260261--0.101--
2016-02-23T16:28:36Mark RoseManual testing261262--0.202--
2010-05-04T02:59:00GrunwalderGIMPManual testing21263--1.049--
2016-02-23T16:28:36Mark RoseManual testing262263--0.645--
2015-01-31T10:43:00snme2pm1Manual testing263264--1.290--
2015-01-31T10:43:00snme2pm1Manual testing264265--2.455--
2015-09-29T08:27:47ramgeisManual testing265266--4.911--
2018-03-05T14:53:06TJAOIManual testing266267--9.82--
2018-06-06T17:06:43ramgeisManual testing267268--19.64--


ECM factoring results:

Old Calculation Method

Total ECM effort:30.740 GHz-days
Estimated T-Level:25.344
DigitsB1CurvesCompleteFacMiss
2011000324 / 1003.2403.853%
2550000324 / 2801.15731.373%
3025000044 / 6400.06993.351%

New Calculation Method

Total ECM effort:30.740 GHz-days
Estimated T-Level:25.344
DigitsB1CompleteFacMiss
201100015.1690.000%
25500001.68418.564%
302500000.14086.967%
3510000000.00999.062%


ECM Summary

B1B2factorcurvesGHz-days
50000500000028015.62
250000400000004415.12


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1997-11-12T00:00:00ANONYMOUSv4_computers0684C70F9D7C526A0.068
1999-01-02T00:00:00Lars Lindleyv4_computers0684C70F9D7C526A0.068
2015-07-10T01:00:00MadPooManual testing0684C70F9D7C526A0.068


PRP results:
No PRP results for M1521757


P-1 factor-bounds graph:
B1 = 10000000, B2 = 200000000 (P-1 stage 2)
B1 = 10000000 (P-1 stage 1)
B1 = 945000, B2 = 27405000 (P-1 stage 2)
B1 = 945000 (P-1 stage 1)
B1 = 80000, B2 = 1340000 (P-1 stage 2)
B1 = 80000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2022-06-01T10:40:12+00:00