is 2 2157721 - 1
has 649539 decimal digits
takes 0.142 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-LE2973F4404E77666double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26713.771067.1642%500000150000000.12305.1700%13.894068.8618%1.6976%
PrimeNet2580.017862.0690%100001700000.00182.8097%0.019663.1347%1.0657%
GPU722620.284764.5161%100001600000.00171.5189%0.286565.0551%0.5390%
Difference+5+13.4862+2.6481%+490000+14840000+0.1213+3.6511%+13.6075+3.8067%+3.8067%

Known prime factors (1 factor, 60.0 bits, 0.00278086% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
215772111554330251855118571960.003267743842968
23 × 3 × 7 × 1593713351
2008-12-21815937133510.12558.278115.461

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-03-07T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.279%
2016-03-29T18:17:05alpertronManual testing5000001500000012---0.123--5.170%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-01-29T00:00:00ANONYMOUSv4_computers21258--0.018--


ECM factoring results:

Old Calculation Method

Total ECM effort:2.236 GHz-days
Estimated T-Level:1.200
DigitsB1CurvesCompleteFacMiss
201100024 / 1000.24078.568%
255000024 / 2800.08691.772%

New Calculation Method

Total ECM effort:2.236 GHz-days
Estimated T-Level:1.200
DigitsB1CompleteFacMiss
20110000.96837.986%
25500000.09091.416%
302500000.00699.432%


ECM Summary

B1B2factorcurvesGHz-days
10.00000e+0
500005000000100.854
50000675000070.684
50000705370470.698


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-02-07T00:00:00ANONYMOUSv4_computersE2973F4404E776660.142


PRP results:
dateuseridcompidcofactorsres64PRP
2017-10-08T23:33:42Oliver KruseGTX-3
1155433025185511857
79914FBD4195E7__no
2017-11-18T20:36:59kkmrkkblmbrbkc4.xlarge
1155433025185511857
79914FBD4195E7__no


P-1 factor-bounds graph:
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
B1 = 2048, B2 = 204800 (P-1 stage 2)
B1 = 2048 (P-1 stage 1)
100
101
102
103
104
105
106
100
101
102
103
104
105
106
107
108
109
1010
TF factor-bounds graph:
267
258
250
260
270
280
290
2100
Last modified: 2022-07-25T19:25:24+00:00