is 2 2543621 - 1
has 765707 decimal digits
takes 0.176 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L8F9A6B4B21814955double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26711.681767.1642 %2230002386975501.32927.1745 %13.010969.5200 %
Target2630.627565.0794 %120009000000.00611.4773 %0.633565.5952 %
Difference+4+11.0543+2.0848 %+211000+237797550+1.3231+5.6972%+12.3774+3.9247 %

Known prime factors (1 factor, 66.7 bits, 0.00262231% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
25436211200097123970048043832166.70223590328983171
2584207 × 9128653
2010-04-30258420791286538.97410.29580.5289

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2003-10-23ANONYMOUSv4_computers2048204800--0.0010.665%
2003-11-08Team Prime Ribv4_computers15000198750--0.0031.627%
2023-01-25USAFSSUSAFSACS223000238697550--1.48010.317%


Trial Factoring results:
5758596061626364656667
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
1999-03-15Brap_Onv4_computers212590.015
2022-03-11LordJuliusManual testing21260
2009-01-31Sturle Sundeaalto.ifi2602610.060


ECM factoring results:
Total ECM effort:5.702 GHz-days
Estimated T-Level:21.015
DigitsB1CompleteFacMiss
20110002.19911.095%
25500000.20381.629%
302500000.01398.716%


ECM Summary

B1B2factorcurvesGHz-days
10.198
50000500000030.198
500006788068505.307


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-05-30ANONYMOUSv4_computers8F9A6B4B218149550.176


PRP results:
dateuseridcompidcofactorsres64
2017-10-14Oliver KruseGTX-0
120009712397004804383
F988AD365C71A8A9
2017-12-01storm55103570_Ivy_Bridge
120009712397004804383
F988AD365C71A8A9


CERT results:
No CERT results for M2543621


P-1 factor-bounds graph:
B1 = 223000, B2 = 238697550 (P-1 stage 2)
B1 = 223000 (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)
102
103
104
105
106
107
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
ECM T-Level=21.01 ~= 53-bit
250
260
270
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Last modified: 2024-03-17T10:05:09+00:00