is 2 251861 - 1
has 75818 decimal digits
takes 0.001 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L63FEED54EC84C4D5double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual270948.740174.2857%100000000020289610196856089,947.026027.9381%90,895.766181.4698%7.1841%
PrimeNet2400.000055.0000%2600700000.000114.2207%0.000161.3993%6.3993%
GPU722440.000059.0909%45001100000.000110.1718%0.000163.2521%4.1612%
Difference+26+948.7401+15.1948%+999995500+202896101858560+89,947.0260+17.7663%+90,895.7660+18.2177%+18.2177%

Known prime factors:
No known factors for M251861

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2000-11-25T00:00:00ANONYMOUSv4_computers950003800000---0.002--1.509%
2001-06-17T00:00:00ANONYMOUSv4_computers10000010000000---0.005--1.889%
2002-06-02T00:00:00ANONYMOUSv4_computers327683276800---0.002--1.017%
2002-08-10T00:00:00ANONYMOUSv4_computers655366553600---0.003--1.522%
2003-03-07T00:00:00ANONYMOUSv4_computers13107213107200---0.007--2.148%
2003-11-08T00:00:00ANONYMOUSv4_computers26214426214400---0.014--2.886%
2011-02-07T22:22:00Jocelyn LaroucheManual testing20000002000000---0.016--1.894%
2012-02-26T15:17:00Jocelyn LaroucheManual testing24819592481959---0.020--2.060%
2013-10-13T19:28:00David Campeaui5-2500k259500072660000---0.052--4.897%
2015-01-16T07:36:00thelegendarymudkipi5-4670k10000000250000000---0.188--6.773%
2016-05-13T23:04:30mognutsManual testing281670400---5.28698e-5--0.072%
2020-01-05T17:55:47nordinordiputer120000000250000000012---2.031--10.748%
2022-02-27T11:45:34-Anonymous-T58101000000000202896101968560---89,947--27.938%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-11-24T00:00:00ANONYMOUSv4_computers252253--0.002--
2000-04-27T00:00:00ANONYMOUSv4_computers21254--0.010--
2022-03-07T05:45:24LordJuliusManual testing254255--0.010--
2001-02-18T00:00:00ANONYMOUSv4_computers21256--0.038--
2002-03-16T00:00:00ANONYMOUSv4_computers21257--0.076--
2004-02-07T00:00:00ANONYMOUSv4_computers21258--0.152--
2008-12-31T22:49:00Sturle Sundegnom.ifi258259--0.152--
2009-01-24T01:02:00Sturle Sundeghini.ifi259260--0.305--
2013-07-15T09:19:00Sid & AndyBuzz260261--0.610--
2015-08-25T13:23:00NRManual testing261262--1.220--
2016-01-28T21:00:45Gordon SpenceManual testing262263--3.898--
2016-01-28T21:00:45Gordon SpenceManual testing263264--7.795--
2018-03-15T10:11:08Gordon SpenceManual testing264265--14.84--
2020-01-01T19:12:56Gordon SpenceManual testing265266--29.67--
2021-05-26T10:22:38Anton RepkoManual testing266269--415.4--
2021-05-26T10:22:38Anton RepkoManual testing269270--474.7--


ECM factoring results:

Old Calculation Method

Total ECM effort:188.982 GHz-days
Estimated T-Level:34.534
DigitsB1CurvesCompleteFacMiss
20110002287 / 10022.8700.000%
25500002287 / 2808.1680.028%
302500002004 / 6403.1314.356%
3510000001420 / 15660.90740.371%

New Calculation Method

Total ECM effort:188.982 GHz-days
Estimated T-Level:34.534
DigitsB1CompleteFacMiss
2011000300.6420.000%
255000056.5660.000%
302500008.2910.025%
3510000000.99137.108%
4030000000.09890.635%
45110000000.00899.181%


ECM Summary

B1B2factorcurvesGHz-days
5000050000002831.692
2500002500000058417.46
10000001000000001,420169.8


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
2016-06-01T06:39:02MadPooManual testing63FEED54EC84C4D50.001


PRP results:
No PRP results for M251861


P-1 factor-bounds graph:
B1 = 1000000000, B2 = 202896101968560 (P-1 stage 2)
B1 = 1000000000 (P-1 stage 1)
B1 = 120000000, B2 = 2500000000 (P-1 stage 2)
B1 = 120000000 (P-1 stage 1)
B1 = 10000000, B2 = 250000000 (P-1 stage 2)
B1 = 10000000 (P-1 stage 1)
B1 = 2595000, B2 = 72660000 (P-1 stage 2)
B1 = 2595000 (P-1 stage 1)
B1 = 2481959 (P-1 stage 1)
B1 = 2000000 (P-1 stage 1)
B1 = 262144, B2 = 26214400 (P-1 stage 2)
B1 = 131072, B2 = 13107200 (P-1 stage 2)
B1 = 100000, B2 = 10000000 (P-1 stage 2)
B1 = 65536, B2 = 6553600 (P-1 stage 2)
B1 = 95000, B2 = 3800000 (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 = 100000 (P-1 stage 1)
B1 = 95000 (P-1 stage 1)
B1 = 65536 (P-1 stage 1)
B1 = 32768 (P-1 stage 1)
B1 = 2816, B2 = 70400 (P-1 stage 2)
B1 = 2816 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2022-03-07T05:45:24+00:00