is 2 2778827 - 1
has 836511 decimal digits
takes 0.215 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L696E28648651CB73double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual26710.693067.1642%2700000840000000.79848.3375%11.491469.9019%2.7377%
PrimeNet2590.027662.7119%120002200000.00262.8579%0.030263.7775%1.0656%
GPU722630.574365.0794%150002400000.00311.7473%0.577465.6895%0.6102%
Difference+4+10.1186+2.0848%+2685000+83760000+0.7954+6.5902%+10.9140+4.2123%+4.2123%

Known prime factors (1 factor, 89.4 bits, 0.00321887% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
27788278436696831243774133249708012789.447151803203856227360200
23 × 52 × 2243 × 2423 × 3463 × 40328843
2017-03-2534634032884373,632,1730.24640.4596

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2003-11-17T00:00:00ANONYMOUSv4_computers2048204800---0.001--0.300%
2010-11-10T22:07:00Jocelyn LaroucheManual testing1500015000---0.002--0.252%
2010-11-27T11:22:00markrtiny1100002392500---0.026--2.937%
2016-08-06T20:01:40Jocelyn LaroucheManual testing15200047850006---0.045--3.611%
2016-12-18T19:43:08Jocelyn Larouchelow 4M182400182400---0.020--1.336%
2017-01-10T10:25:03Jocelyn Larouchelow 4M218880218880---0.025--1.462%
2017-01-10T10:25:06Jocelyn Larouchelow 4M262656262656---0.029--1.596%
2017-03-11T20:25:00Jocelyn Larouchelow 4M31518731518706---0.053--3.650%
2017-03-25T16:53:32mikrMSI270000084000000122789.4470.7980.4291.5978.338%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2016-02-23T16:29:21Mark RoseManual testing21260--0.055--
2009-01-28T03:24:00Sturle Sundeghini.ifi260261--0.055--
2012-03-29T12:16:00Grant McCrackenthumper261262--0.111--
2013-01-10T10:21:00dbaughManual testing262263--0.353--
2015-04-21T09:20:00VictordeHollanderManual testing263264--0.707--
2015-04-21T09:20:00VictordeHollanderManual testing264265--1.345--
2015-12-12T20:00:03omylistManual testing265266--2.689--


ECM factoring results:

Old Calculation Method

Total ECM effort:2.185 GHz-days
Estimated T-Level:1.050
DigitsB1CurvesCompleteFacMiss
201100021 / 1000.21080.973%
255000021 / 2800.07592.762%

New Calculation Method

Total ECM effort:2.185 GHz-days
Estimated T-Level:1.050
DigitsB1CompleteFacMiss
20110000.67750.793%
25500000.06194.061%
302500000.00499.624%


ECM Summary

B1B2factorcurvesGHz-days
500005000000212.185


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-07-30T00:00:00Martijn Ottov4_computers696E28648651CB730.215


PRP results:
dateuseridcompidcofactorsres64PRP
2017-10-21T05:02:48Oliver KruseGTX-0
843669683124377413324970801
6556E68FFA85A9__no
2017-12-06T06:41:58kkmrkkblmbrbkc4.xlarge
843669683124377413324970801
6556E68FFA85A9__no


P-1 factor-bounds graph:
B1 = 2700000, B2 = 84000000 (P-1 stage 2)
B1 = 2700000 (P-1 stage 1)
B1 = 315187, B2 = 3151870 (P-1 stage 2)
B1 = 152000, B2 = 4785000 (P-1 stage 2)
B1 = 315187 (P-1 stage 1)
B1 = 262656 (P-1 stage 1)
B1 = 110000, B2 = 2392500 (P-1 stage 2)
B1 = 218880 (P-1 stage 1)
B1 = 182400 (P-1 stage 1)
B1 = 152000 (P-1 stage 1)
B1 = 110000 (P-1 stage 1)
B1 = 15000 (P-1 stage 1)
B1 = 2048, B2 = 204800 (P-1 stage 2)
B1 = 2048 (P-1 stage 1)
102
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105
106
107
102
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104
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108
TF factor-bounds graph:
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265
264
263
262
261
260
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260
270
280
290
2100
Last modified: 2017-12-06T06:41:58+00:00