is 2 2564381 - 1
has 771956 decimal digits
takes 0.178 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L627E0CF183B66F0Bdouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26711.587267.1642%2250002386975501.32937.1918%12.916569.5257%
Target2630.622465.0794%120001800000.00211.4797%0.624565.5961%
Difference+4+10.9648+2.0848%+213000+238517550+1.3272+5.7121%+12.2920+3.9296%

Known prime factors (2 factors, 138.7 bits, 0.00540904% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
2564381808088946624063109132066.13115756023512576
29 × 211 × 145845893
2010-05-125121458458939.7910.79921.4926
256438170463542241173026769992272.5771373889883000479
3 × 13 × 156631 × 224910431
2023-01-25156631224910431453.581.24732.3018

1 Composite Factors:
P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-10-23ANONYMOUSv4_computers2048204800---0.001--0.293%
2003-11-08Team Prime Ribv4_computers15000198750---0.003--0.885%
2023-01-25USAFSSUSAFSACS2250002386975502272.5771.3290.3562.6597.192%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-03-15foxkidv4_computers21259--0.030--
2022-03-11LordJuliusManual testing21260--0.060--
2009-02-01Sturle Sundegowin.ifi260261--0.060--


ECM factoring results:
Total ECM effort:0.277 GHz-days
Estimated T-Level:0.577
DigitsB1CompleteFacMiss
20110000.11589.102%
25500000.01198.938%


ECM Summary

B1B2factorcurvesGHz-days
10.00000e+0
50000500000030.277


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1997-01-01Joe Decker627E0CF183B66F0B0.178
1999-03-26foxkidv4_computers627E0CF183B66F0B0.178


PRP results:
dateuseridcompidcofactorsres64PRP
2017-10-15Oliver KruseGTX-3
80808894662406310913
F8CE288BD1EC7C__no
2017-12-01kkmrkkblmbrbkc4.xlarge
80808894662406310913
F8CE288BD1EC7C__no
2023-01-25LordJuliusWhiteBox
80808894662406310913
7046354224117302676999
F8CE288BD1EC7CC2no


P-1 factor-bounds graph:
B1 = 225000, B2 = 238697550 (P-1 stage 2)
B1 = 225000 (P-1 stage 1)
B1 = 15000, B2 = 198750 (P-1 stage 2)
B1 = 15000 (P-1 stage 1)
B1 = 2048, B2 = 204800 (P-1 stage 2)
B1 = 2048 (P-1 stage 1)
101
102
103
104
105
106
101
102
103
104
105
106
107
108
109
TF factor-bounds graph:
261
260
259
this exponent TF target: 63
TF double-checked to: 67.7
ECM T-Level=0.58 ~= -15-bit
250
260
270
280
Last modified: 2023-03-25T13:08:14+00:00