is 2 1621537 - 1
has 488132 decimal digits
takes 0.072 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L8DE2404F84F4F32Edouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26718.324568.6567 %500000150000000.08354.9952 %18.408170.2224 %
Target2610.189465.5738 %65003000000.00151.0595 %0.190965.9385 %
Difference+6+18.1351+3.0829 %+493500+14700000+0.0821+3.9357%+18.2172+4.2839 %

Known prime factors (1 factor, 63.7 bits, 0.00392821% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
1621537149567707528223301832063.6974611911647043
31 × 10343 × 14383771
2008-04-1910343143837710.98430.05140.0948

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2016-03-17alpertronManual testing5000001500000012
skipped known factor: 14956770752822330183
---8.750%


Trial Factoring results:
5758596061626364656667
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
1998-11-07ANONYMOUSv4_computers212570.012
2004-07-26ANONYMOUSv4_computers212570.012
2003-07-06ANONYMOUSv4_computers212580.024


ECM factoring results:
Total ECM effort:31.383 GHz-days
Estimated T-Level:25.716
DigitsB1CompleteFacMiss
201100014.5770.000%
25500001.66718.874%
302500000.14386.662%
3510000000.01099.007%


ECM Summary

B1B2factorcurvesGHz-days
10.085
50000500000024913.98
250000400000005017.32


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1998-11-21ANONYMOUSv4_computers8DE2404F84F4F32E0.072
2004-07-26ANONYMOUSv4_computers8DE2404F84F4F32E0.072


PRP results:
dateuseridcompidcofactorsres64
2017-10-02Oliver KruseGTX-2
14956770752822330183
2E4B29911728631C
2017-11-01kkmrkkblmbrbkc4.xlarge
14956770752822330183
2E4B29911728631C


CERT results:
No CERT results for M1621537


P-1 factor-bounds graph:
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
103
104
105
106
103
104
105
106
107
108
TF factor-bounds graph:
258
257
this exponent TF target: 61
TF double-checked to: 67
ECM T-Level=25.72 ~= 69-bit
250
260
270
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Last modified: 2024-03-03T02:29:32+00:00