is 2 1521913 - 1
has 458142 decimal digits
takes 0.068 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L5BD4AC9917E7757Bdouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26719.524168.6567 %500000150000000.08354.9571 %19.607670.2104 %
Target2610.201865.5738 %65002750000.00141.0130 %0.203265.9225 %
Difference+6+19.3222+3.0829 %+493500+14725000+0.0822+3.9441%+19.4044+4.2879 %

Known prime factors (1 factor, 72.1 bits, 0.00473742% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
152191350594391121692246130012272.0991662197218950500
22 × 53 × 59 × 56345668439
2009-04-12125563456684391,120.8198.83371.35

P-1 results:
dateusercompB1B2BSstagefactordigitsbits*GHz-daysFac Prob
2016-03-17alpertronManual testing5000001500000012---8.690%


Trial Factoring results:
5758596061626364656667
 BitsFactor
dateuseridcompidfromtofactorbits*digitsGHz-days
1997-11-12ANONYMOUSv4_computers212560.006
2022-03-08LordJuliusManual testing256257
2003-08-08ANONYMOUSv4_computers212580.025


ECM factoring results:
Total ECM effort:31.104 GHz-days
Estimated T-Level:25.715
DigitsB1CompleteFacMiss
201100014.5380.000%
25500001.66418.942%
302500000.14386.682%
3510000000.01099.008%


ECM Summary

B1B2factorcurvesGHz-days
10.127
50000500000024813.80
250000400000005017.18


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1997-11-12ANONYMOUSv4_computers5BD4AC9917E7757B0.068


PRP results:
dateuseridcompidcofactorsres64
2017-10-01Oliver KruseGTX-1
5059439112169224613001
046AAAF7C6E5B38A
2017-10-29kkmrkkblmbrbkc4.xlarge
5059439112169224613001
046AAAF7C6E5B38A


CERT results:
No CERT results for M1521913


P-1 factor-bounds graph:
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
101
102
103
104
105
106
101
102
103
104
105
106
107
108
109
1010
1011
TF factor-bounds graph:
258
257
256
this exponent TF target: 61
TF double-checked to: 67
ECM T-Level=25.71 ~= 69-bit
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Last modified: 2024-03-13T02:15:48+00:00