is 2 1872271 - 1
has 563610 decimal digits
takes 0.102 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
Actual26715.870568.6567%500000150000000.10155.0825%15.972070.2498%1.5930%
PrimeNet2570.010363.1579%90001600000.00143.0298%0.011664.2741%1.1162%
GPU722610.164165.5738%100001500000.00141.6900%0.165566.1556%0.5818%
Difference+6+15.7065+3.0829%+490000+14850000+0.1001+3.3925%+15.8065+4.0942%+4.0942%

Known prime factors (3 factors, 133.6 bits, 0.00713327% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
187227128645746311031.416765
32 × 5 × 17
-9171.781e-107.422e-71.441e-6
1872271263765538491134.6197044
22 × 3 × 587
2008-07-1545871.864e-92.813e-64.673e-6
18722712116134416739000544312167.52056512503177665
5 × 11302500635533
2018-04-1451130250063553331.02448,44090,472

4 Composite Factors:
exponentprime factorscomposite factordigitsbits*
1872271755576070090508047192066.034
18722716061824965976522707525617399613098.936
1872271558163333948384548354330255491931102.139
18722711598900526382923440648207248877845165988941133.554
P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2016-03-16T12:38:18alpertronManual testing5000001500000012-
skipped known factor: 2864574631
skipped known factor: 26376553849
--0.101--5.083%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
2008-07-15T07:47:00J FeitsmaManual testing??34.619116.41365e-100.2171.36905e-9


ECM factoring results:

Old Calculation Method

Total ECM effort:19.828 GHz-days
Estimated T-Level:24.607
DigitsB1CurvesCompleteFacMiss
2011000258 / 1002.5807.480%
2550000258 / 2800.92139.729%

New Calculation Method

Total ECM effort:19.828 GHz-days
Estimated T-Level:24.607
DigitsB1CompleteFacMiss
20110008.8140.015%
25500000.79944.988%
302500000.04995.179%
3510000000.00299.773%


ECM Summary

B1B2factorcurvesGHz-days
500005000000352.424
50000500000020.138
50000660000021416.71
50000675000070.553


Lucas-Lehmer results:
No L-L results for M1872271


PRP results:
dateuseridcompidcofactorsres64PRP
2017-10-04T11:39:44Oliver KruseGTX-1
2864574631
26376553849
0BC5E441CE8C5F__no
2017-11-07T16:20:33kkmrkkblmbrbkc4.xlarge
2864574631
26376553849
0BC5E441CE8C5F__no
2018-04-18T09:51:25Oliver KruseGTX-1
2864574631
26376553849
211613441673900054431
9C35532572225F__no
2018-04-18T09:57:20ATHwork200558
2864574631
26376553849
211613441673900054431
9C35532572225F__no


P-1 factor-bounds graph:
B1 = 500000, B2 = 15000000 (P-1 stage 2)
B1 = 500000 (P-1 stage 1)
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TF factor-bounds graph:
267
2
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Last modified: 2021-09-17T08:22:54+00:00