is 2 1422821 - 1
has 428312 decimal digits
takes 0.054 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L78AAF323E7A0C94Ddouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26841.892069.1176%14228211565103100.54667.4407%42.438671.4155%2.2979%
PrimeNet2560.006762.5000%65001100000.00072.7708%0.007463.5391%1.0391%
GPU722600.107965.0000%6000800000.00061.3022%0.108565.4558%0.4558%
Difference+8+41.7841+4.1176%+1416821+156430310+0.5460+6.1384%+42.3301+5.9597%+5.9597%

Known prime factors:
No known factors for M1422821

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-09-21T00:00:00Team Prime Ribv4_computers15000232500---0.001--0.703%
2009-07-30T21:44:00markrlounge2000005000000---0.026--3.117%
2014-11-10T23:29:00Jocelyn LaroucheManual testing245110245110---0.014--1.217%
2015-01-15T22:03:00Jocelyn LaroucheManual testing367665367665---0.020--1.484%
2015-02-15T21:12:00Jocelyn LaroucheManual testing404431404431---0.022--1.551%
2015-02-20T16:55:00Jocelyn LaroucheManual testing444874444874---0.025--1.620%
2015-03-11T16:22:00alpertronManual testing200000060000000---0.286--6.624%
2016-08-17T01:56:26Bruno Victal5820K-factoring25000006250000012---0.319--6.795%
2016-08-27T10:53:40Bruno VictalManual testing25000006250000012---0.319--6.795%
2018-05-25T20:22:28Jocelyn Larouchelow 4M142282114228210012---0.504--7.338%
2018-10-15T08:20:49Jocelyn Larouchelow 4M142282115651031012---0.547--7.441%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2001-10-20T00:00:00ANONYMOUSv4_computers21257--0.013--
2003-07-13T00:00:00ANONYMOUSv4_computers21258--0.027--
2016-02-23T16:28:31Mark RoseManual testing258260--0.081--
2009-02-15T09:11:00Sturle Sundeothello.ifi260261--0.108--
2016-02-23T16:28:31Mark RoseManual testing261262--0.216--
2011-04-05T20:59:00GrunwalderGIMPManual testing21263--1.122--
2016-02-23T16:28:31Mark RoseManual testing262263--0.690--
2015-03-17T06:25:00snme2pm1Manual testing263264--1.380--
2015-03-17T06:25:00snme2pm1Manual testing264265--2.626--
2015-09-29T08:27:45ramgeisManual testing265266--5.252--
2018-04-30T12:03:48TJAOIManual testing266267--10.50--
2020-04-07T16:27:52YxinityManual testing267268--21.01--


ECM factoring results:

Old Calculation Method

Total ECM effort:26.343 GHz-days
Estimated T-Level:25.391
DigitsB1CurvesCompleteFacMiss
2011000301 / 1003.0104.855%
2550000301 / 2801.07534.064%
3025000050 / 6400.07892.479%

New Calculation Method

Total ECM effort:26.343 GHz-days
Estimated T-Level:25.391
DigitsB1CompleteFacMiss
201100014.6540.000%
25500001.67418.740%
302500000.14486.623%
3510000000.01099.005%


ECM Summary

B1B2factorcurvesGHz-days
50000500000025111.84
250000400000005014.50


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
2015-07-19T16:38:00MadPooManual testing78AAF323E7A0C94D0.054


PRP results:
No PRP results for M1422821


P-1 factor-bounds graph:
B1 = 1422821, B2 = 156510310 (P-1 stage 2)
B1 = 1422821, B2 = 142282100 (P-1 stage 2)
B1 = 2500000, B2 = 62500000 (P-1 stage 2)
B1 = 2000000, B2 = 60000000 (P-1 stage 2)
B1 = 2500000 (P-1 stage 1)
B1 = 2000000 (P-1 stage 1)
B1 = 1422821 (P-1 stage 1)
B1 = 200000, B2 = 5000000 (P-1 stage 2)
B1 = 444874 (P-1 stage 1)
B1 = 404431 (P-1 stage 1)
B1 = 367665 (P-1 stage 1)
B1 = 245110 (P-1 stage 1)
B1 = 200000 (P-1 stage 1)
B1 = 15000, B2 = 232500 (P-1 stage 2)
B1 = 15000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2022-03-10T10:37:56+00:00