is 2 1667873 - 1
has 502080 decimal digits
takes 0.078 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
factored, 0 LL tests remaining
ResidueStatus
L-L967CCF4893FE1C44double-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual26835.737169.1176%250000005567626264202,071.621720.7199%2,107.358875.5164%
Target2610.184265.5738%7000800000.00071.2064%0.184965.9891%
Difference+7+35.5529+3.5439%+24993000+556762546420+2,071.6210+19.5135%+2,107.1739+9.5273%

Known prime factors (1 factor, 125.5 bits, 0.00752671% known):
Remaining cofactor is not a probable-prime

P-1GHz-days
exponentfactordigitsbits*kdate foundmin B1min B2min. TFmin. P-1normal P-1
16678736166933518320155539594671573637558050338125.53618487419360827099963830194426187
7 × 37 × 251 × 2251 × 550757 × 7085809 × 32372619661
2023-01-087085809323726196611.015e+11120.82224.80

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2012-02-29AxonManual testing100000100000---0.007--0.763%
2012-02-29AxonManual testing200000200000---0.014--1.126%
2012-02-29AxonManual testing300000300000---0.020--1.381%
2012-02-29AxonManual testing400000400000---0.027--1.582%
2012-02-29AxonManual testing500000500000---0.034--1.749%
2012-02-29AxonManual testing600000600000---0.041--1.892%
2012-02-29AxonManual testing700000700000---0.048--2.019%
2012-02-29AxonManual testing800000800000---0.055--2.132%
2012-02-29AxonManual testing900000900000---0.061--2.235%
2012-02-29AxonManual testing10000001000000---0.068--2.329%
2012-03-01AxonManual testing10000008000000---0.094--4.298%
2012-03-01AxonManual testing100000020000000---0.139--5.194%
2018-01-22Jocelyn Larouchelow 4M16678732000000012---0.182--5.434%
2018-02-04Jocelyn Larouchelow 4M16678734000000012---0.256--6.184%
2018-02-21Jocelyn Larouchelow 4M16678738000000012---0.405--6.944%
2018-05-22VictordeHollanderManual testing1000000020000000012---1.389--9.093%
2023-01-03Jocelyn LaroucheManual testing16688731152946410---4.394--9.935%
2023-01-08Naegi Makoto5950X2500000055676262642038125.5362,0720.1574,14320.720%


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1998-11-21ANONYMOUSv4_computers21257--0.012--
2001-12-01ANONYMOUSv4_computers21257--0.012--
2016-02-23Mark RoseManual testing257260--0.081--
2010-04-29Architects Cubedi4l_1260261--0.092--
2016-02-23Mark RoseManual testing261262--0.184--
2010-08-22GrunwalderGIMPManual testing21263--0.957--
2016-02-23Mark RoseManual testing262263--0.589--
2015-05-11omylistManual testing263264--1.177--
2015-05-12monstManual testing264265--2.240--
2015-10-11ramgeisManual testing265266--4.480--
2017-09-29TJAOIManual testing266267--8.961--
2019-07-31TJAOIManual testing267268--17.92--


ECM factoring results:
Total ECM effort:16.610 GHz-days
Estimated T-Level:24.982
DigitsB1CompleteFacMiss
201100010.7690.002%
25500000.99636.919%
302500000.06393.908%
3510000000.00399.707%


ECM Summary

B1B2factorcurvesGHz-days
50000500000028016.61


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1999-02-21bezaharv4_computers967CCF4893FE1C440.078
2015-07-06MadPooManual testing967CCF4893FE1C440.078


PRP results:
dateuseridcompidcofactorsres64PRP
2023-01-08Naegi Makoto5950X
61669335183201555395946715736375580503
B854540FDA5DE819no


P-1 factor-bounds graph:
B1 = 25000000, B2 = 556762626420 (P-1 stage 2)
B1 = 1668873, B2 = 1152946410 (P-1 stage 2)
B1 = 25000000 (P-1 stage 1)
B1 = 10000000, B2 = 200000000 (P-1 stage 2)
B1 = 10000000 (P-1 stage 1)
B1 = 1667873, B2 = 80000000 (P-1 stage 2)
B1 = 1667873, B2 = 40000000 (P-1 stage 2)
B1 = 1667873, B2 = 20000000 (P-1 stage 2)
B1 = 1000000, B2 = 20000000 (P-1 stage 2)
B1 = 1668873 (P-1 stage 1)
B1 = 1667873 (P-1 stage 1)
B1 = 1000000, B2 = 8000000 (P-1 stage 2)
B1 = 1000000 (P-1 stage 1)
B1 = 900000 (P-1 stage 1)
B1 = 800000 (P-1 stage 1)
B1 = 700000 (P-1 stage 1)
B1 = 600000 (P-1 stage 1)
B1 = 500000 (P-1 stage 1)
B1 = 400000 (P-1 stage 1)
B1 = 300000 (P-1 stage 1)
B1 = 200000 (P-1 stage 1)
B1 = 100000 (P-1 stage 1)
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TF factor-bounds graph:
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Last modified: 2023-01-08T11:52:14+00:00