is 2 21221 - 1
has 6389 decimal digits
takes 0.000 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
-unknown- primality tests remaining
ResidueStatus
L-L-unknown--unknown-
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbabilityProb over default TF
Actual2671,400.212977.6119%500000000100000000000.472213.3915%1,400.685080.6100%2.9981%
PrimeNet2400.000062.5000%500100000.00003.7538%0.000063.9077%1.4077%
GPU722440.000165.9091%500100000.00001.5872%0.000166.4502%0.5411%
Difference+23+1,400.2128+11.7028%+499999500+9999990000+0.4722+11.8042%+1,400.6849+14.1598%+14.1598%

Known prime factors (4 factors, 195.3 bits, 0.92023791% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
21221636631619.28015
3 × 5
-353.302e-121.443e-92.833e-9
212212546521721.28060
22 × 3 × 5
2008-08-26451.334e-111.881e-93.777e-9
212216948559700940791549.30416371895059
32 × 13 × 9397 × 14891
2008-08-269397148910.00434.499e-68.874e-6
212215426469499561032346357842978347932105.4201278561212846009223495085759
107 × 241 × 17921 × 2766677034942919117
2021-10-191792127666770349429191176.376e+1269,941,595130,631,423

11 Composite Factors:
exponentprime factorscomposite factordigitsbits*
2122116211942107511340.560
212214423668510969636078492168.584
2122117694653198199441491592270.584
2122111264964760222908636232433292889.864
212213454658703975039583694139933148601924938124.700
2122113818618536491659651679520659065472655939126.700
212218797360937505221775708384916701510922398272944145.980
212213770614728303412529279057311940618561522992084147154.723
2122124004902250945298219274555355580679354409439734926
671
53174.004
2122196019495885339343774722343050603359199080913249944
161
53176.004
2122161128987684979471766645259978648667170270080883225
201161591
59195.284
P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2016-11-19T00:49:55kkmrkkblmbrbkManual testing5000000001000000000012-
skipped known factor: 636631
skipped known factor: 2546521
skipped known factor: 694855970094079
--0.472--13.391%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2008-08-26T19:59:00ANONYMOUSManual testing??21.28071.70977e-132.09559e-55.27628e-13
2008-08-26T19:59:00ANONYMOUSManual testing??49.304150.0011.40536e-50.002


ECM factoring results:

Old Calculation Method

Total ECM effort:18.303 GHz-days
Estimated T-Level:35.426
DigitsB1CurvesCompleteFacMiss
20110002326 / 10023.2600.000%
25500002326 / 2808.3070.024%
302500002296 / 6403.5882.759%
3510000001821 / 15801.15331.572%
403000000400 / 47000.08591.841%

New Calculation Method

Total ECM effort:18.303 GHz-days
Estimated T-Level:35.426
DigitsB1CompleteFacMiss
2011000323.5510.000%
255000065.4580.000%
3025000010.6420.002%
3510000001.40424.560%
4030000000.15585.626%
45110000000.01598.511%
50440000000.00199.871%


ECM Summary

B1B2factorcurvesGHz-days
500005000000300.010
250000250000004750.793
10000001000000001,4219.488
30000003000000003677.351
3000000300000000330.661


Lucas-Lehmer results:
No L-L results for M21221


PRP results:
dateuseridcompidcofactorsres64PRP
2017-09-21T19:26:45Oliver KrusePRP
636631
2546521
694855970094079
2132A74E6208B0__no
2017-09-21T20:26:59Oliver KruseManual testing
636631
2546521
694855970094079
2132A74E6208B0__no
2017-10-12T16:29:44kkmrkkblmbrbkManual testing
636631
2546521
694855970094079
2132A74E6208B0__no
2020-04-17T13:49:05Oliver KruseManual testing
636631
2546521
694855970094079
C4376C53C4D873__no
2021-10-19T03:05:43H Michaelson
636631
2546521
694855970094079
54264694995610323463578429783479
C4376C53C4D873EEno


P-1 factor-bounds graph:
B1 = 500000000, B2 = 10000000000 (P-1 stage 2)
B1 = 500000000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2021-10-21T07:19:59+00:00