is 2 42783553 - 1
has 12879133 decimal digits
takes 63.061 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L7FB476955C19A7A6double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual27344.709864.3836 %570000114000002.47934.0030 %47.189165.8093 %
Target27222.352863.8889 %300000450000005.84623.8777 %28.199065.2892 %
Difference+1+22.3570+0.4947 %+270000-33600000-3.3669+0.1252%+18.9901+0.5201 %

Known prime factors (1 factor, 82.8 bits, 0.00019347% known):
Remaining cofactor is PRP status unknown

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
4278355382599320355326014445620332582.77296531627884348472
23 × 3 × 107 × 421 × 45191 × 1975789
2018-12-2045191197578945,2520.32140.4297

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2008-04-03ANONYMOUSv4_computers715000715000--1.5282.072%
2018-12-20Architects Cubedgpu72570000114000001222582.7722.4794.411%


Trial Factoring results:
5758596061626364656667686970717273
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
2007-07-04tmorrowv4_computers212680.699
2014-03-05LaurVManual testing2682691.397
2015-02-23chalsallManual testing2692702.795
2015-04-13Mark RoseManual testing2702715.589
2015-09-03ANONYMOUSManual testing27127211.18
2018-12-07Robin89Manual testing27227322.36


ECM factoring results:
No ECM results for M42783553


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
2008-05-21ANONYMOUSv4_computers7FB476955C19A7A663.06
2016-09-14pcbbcWork7FB476955C19A7A663.06


PRP results:
No PRP results for M42783553


CERT results:
No CERT results for M42783553


P-1 factor-bounds graph:
B1 = 570000, B2 = 11400000 (P-1 stage 2)
B1 = 715000 (P-1 stage 1)
B1 = 570000 (P-1 stage 1)
103
104
105
106
103
104
105
106
107
108
TF factor-bounds graph:
273
272
271
270
269
268
this exponent TF target: 72
TF double-checked to: 67
250
260
270
280
290
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Last modified: 2024-03-13T02:15:48+00:00