is 2 1237 - 1
has 373 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-LDF5E6622F83F5BE2double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26724,020.951983.5821%100000000000022328434186491294782,876,234.795343.3852%2,900,255.747290.7050%7.1229%
PrimeNet2400.000172.5000%500100000.00001.6958%0.000172.9663%0.4663%
GPU722440.001975.0000%500100000.00000.6498%0.001975.1624%0.1624%
Difference+23+24,020.9500+8.5821%+999999999500+2232843418649119478+2,876,234.7953+42.7354%+2,900,255.7453+15.5426%+15.5426%

Known prime factors (1 factor, 230.6 bits, 18.63838709% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
123725382071298406877993352032594928704761862488966164
01346500027311795983
70230.55710259527606470039609277296926001901682240294650834
28191794675550443

3 × 7 × 110421384041193593117465987 × 442440509040507330087115446251753610709
2010-11-021104213840411935931174659874424405090405073300871154462517536107091.422e+145.699e+261.064e+27

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2001-02-11T00:00:00ANONYMOUSv4_computers100001000000---1.51169e-6--0.205%
2001-02-11T00:00:00ANONYMOUSv4_computers1000000100000000---0.000--3.239%
2001-05-13T00:00:00ANONYMOUSv4_computers30000000004290000000---0.073--9.911%
2002-05-25T00:00:00ANONYMOUSv4_computers10737418244290000000---0.030--9.927%
2002-07-27T00:00:00ANONYMOUSv4_computers21474836484290000000---0.054--9.937%
2002-08-17T00:00:00ANONYMOUSv4_computers3030---7.09292e-10--0.000%
2002-09-14T00:00:00ANONYMOUSv4_computers32212254724290000000---0.078--9.903%
2002-11-16T00:00:00Jocelyn Larouchev4_computers42940000004294000000---0.102--9.863%
2002-12-25T00:00:00ANONYMOUSv4_computers42900000002147483647---0.101--9.861%
2003-09-29T00:00:00ANONYMOUSv4_computers1000000100000000---0.000--3.239%
2003-11-28T00:00:00ANONYMOUSv4_computers1000000100000000---0.000--3.239%
2004-02-14T00:00:00Johnson Lauv4_computers444400---6.65143e-9--0.000%
2008-10-22T14:45:00Markus TervoorenManual testing450000000004500000000000---6.803--21.990%
2021-03-27T16:37:19nordiManual testing10000000000002232843418649129478---2,876,235--43.385%


P+1 Factoring results:
dateuseridcompidb1b2startfactorSmoothdigitsbits*ghz-days
2021-07-19T04:22:32ViliamF3100000000022100000000027--0.314


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2002-08-24T00:00:00ANONYMOUSv4_computers21250--0.121--
1998-07-29T00:00:00ANONYMOUSv4_computers251253--0.728--
1999-12-01T00:00:00ANONYMOUSv4_computers253254--0.970--
2000-01-19T00:00:00ANONYMOUSv4_computers254255--1.940--
2000-07-03T00:00:00ANONYMOUSv4_computers21256--7.760--
2002-07-20T00:00:00Alex Kruppav4_computers21257--15.52--
TF assumed completed to 67 but no detailed record exists
2010-06-14T18:26:00chalsallManual testing258259--31.04--
2010-06-22T15:36:00ANONYMOUSManual testing259260--62.08--


ECM factoring results:

Old Calculation Method

Total ECM effort:18,220.430 GHz-days
Estimated T-Level:54.639
DigitsB1CurvesCompleteFacMiss
201100043993 / 100439.9300.000%
255000043993 / 280157.1180.000%
3025000043892 / 64068.5810.000%
35100000043151 / 158027.3110.000%
40300000043146 / 47009.1800.010%
451100000043146 / 97004.4481.170%
504400000043146 / 171002.5238.020%
5511000000043145 / 465000.92839.540%
6026000000039822 / 1120000.35670.078%
6580000000026190 / 3600000.07392.983%

New Calculation Method

Total ECM effort:18,220.430 GHz-days
Estimated T-Level:54.639
DigitsB1CompleteFacMiss
201100021,084.6390.000%
25500009,758.4790.000%
302500003,457.0040.000%
3510000001,126.8010.000%
403000000321.2260.000%
451100000082.6810.000%
504400000019.1990.000%
551100000004.0961.665%
602600000000.81044.484%


ECM Summary

B1B2factorcurvesGHz-days
10.00000e+0
5000050000001010.002
250000250000007410.063
110000000110000000003,323124.4
2600000002600000000013,6311,206
8000000008000000000010127.49
8500000008500000000018,4695,341
29000000002900000000005,1185,050
76000000007600000000002,4966,454
various1318.4410


Lucas-Lehmer results:
No L-L results for M1237


PRP results:
dateuseridcompidcofactorsres64PRP
2017-09-25T08:10:48csabaoffice7F72EDA0088CF1__?
2017-09-26T00:20:42George WoltmanManual testing
25382071298406877993352032594928704761862488966164
01346500027311795983
7F72EDA0088CF1__no
2017-10-02T09:48:14kkmrkkblmbrbkManual testing
25382071298406877993352032594928704761862488966164
01346500027311795983
7F72EDA0088CF1__no
2020-04-17T12:30:31Oliver KruseIOS-1
25382071298406877993352032594928704761862488966164
01346500027311795983
8E671C85179020B6no
2020-08-12T10:14:45_p95holder_TFL16_PRPt11-E_b
25382071298406877993352032594928704761862488966164
01346500027311795983
8E671C85179020B6no


P-1 factor-bounds graph:
B1 = 1000000000000, B2 = 2232843418649129478 (P-1 stage 2)
B1 = 1000000000000 (P-1 stage 1)
B1 = 45000000000, B2 = 4500000000000 (P-1 stage 2)
B1 = 45000000000 (P-1 stage 1)
B1 = 4294000000 (P-1 stage 1)
B1 = 4290000000 (P-1 stage 1)
B1 = 3221225472, B2 = 4290000000 (P-1 stage 2)
B1 = 3221225472 (P-1 stage 1)
B1 = 3000000000, B2 = 4290000000 (P-1 stage 2)
B1 = 3000000000 (P-1 stage 1)
B1 = 2147483648, B2 = 4290000000 (P-1 stage 2)
B1 = 2147483648 (P-1 stage 1)
B1 = 1073741824, B2 = 4290000000 (P-1 stage 2)
B1 = 1073741824 (P-1 stage 1)
B1 = 1000000, B2 = 100000000 (P-1 stage 2)
B1 = 1000000 (P-1 stage 1)
B1 = 10000, B2 = 1000000 (P-1 stage 2)
B1 = 44, B2 = 4400 (P-1 stage 2)
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TF factor-bounds graph:
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Last modified: 2022-04-07T14:14:38+00:00