is 2 19387 - 1
has 5837 decimal digits
takes 0.000 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L-unknown--unknown-
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual2671,532.672377.6119%540000000015129309322837710351,594.718735.6751%353,127.391085.5989%
Target2440.000165.9091%500800000.00001.5449%0.000166.4358%
Difference+23+1,532.6722+11.7028%+5399999500+15129309322757710+351,594.7187+34.1302%+353,127.3909+19.1631%

Known prime factors (3 factors, 216.2 bits, 1.11495611% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
193871080102890391236.6522785637
17 × 163861
-171638619.216e-73.815e-67.112e-6
193876176018879531239.16815928248
23 × 3 × 7 × 94811
2008-08-268948116.319e-62.207e-64.115e-6
19387175966061749500528799563618168370868107730343140.33645382488716536990973220100626288458273
13 × 19 × 23 × 41 × 277 × 2803 × 4831 × 217852429 × 238439032782077
2023-04-192178524292384390327820777.563e+125,541.210,349

4 Composite Factors:
P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2022-02-06Lisander ViaeneManual testing5000050000---2.13271e-5--0.222%
2023-04-19JacobZGreatLakes54000000001512930932283771043140.336351,5951.14060e-5703,18935.675%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2008-08-26ANONYMOUSManual testing??39.168122.54134e-60.0005.57773e-5


ECM factoring results:
Total ECM effort:21.133 GHz-days
Estimated T-Level:36.176
DigitsB1CompleteFacMiss
2011000419.5390.000%
255000088.7890.000%
3025000014.8130.000%
3510000002.03613.060%
4030000000.23579.048%
45110000000.02497.659%
50440000000.00299.790%


ECM Summary

B1B2factorcurvesGHz-days
5000050000001630.050
250000250000005680.872
10000001000000001,4218.722
300000030000000062411.49


Lucas-Lehmer results:
No L-L results for M19387


PRP results:
dateuseridcompidcofactorsres64PRP
2017-09-21Oliver KrusePRP
108010289039
617601887953
56D64A789EF814__no
2017-09-21Oliver KruseManual testing
108010289039
617601887953
56D64A789EF814__no
2017-10-12kkmrkkblmbrbkManual testing
108010289039
617601887953
56D64A789EF814__no
2020-04-17Oliver KruseManual testing
108010289039
617601887953
DB8C8FEC79DE8D__no
2023-04-19JacobZGreatLakes
108010289039
617601887953
1759660617495005287995636181683708681077303
DB8C8FEC79DE8D85no


P-1 factor-bounds graph:
B1 = 5400000000, B2 = 15129309322837710 (P-1 stage 2)
B1 = 5400000000 (P-1 stage 1)
B1 = 50000 (P-1 stage 1)
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TF factor-bounds graph:
2
this exponent TF target: 44
TF double-checked to: 67.9
ECM T-Level=36.18 ~= 104-bit
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Last modified: 2023-07-11T14:45:05+00:00