is 2 248851 - 1
has 74912 decimal digits
takes 0.001 GHz-days to do one PRP test
Last-known PrimeNet details:
Exponent is not assigned to anyone
0 primality tests remaining
ResidueStatus
L-L02A346BFE956DDEDdouble-checked
PRP-unknown--unknown-

 Trial FactoringP-1 FactoringCombined
LimitGHz-daysProbabilityB1B2GHz-daysProbabilityGHz-daysProbability
Actual267119.404573.1343%26300000028654401075301,272.209124.1984%1,391.613679.6354%
Target2440.000059.0909%45001100000.000110.1530%0.000163.2444%
Difference+23+119.4044+14.0434%+262995500+2865439997530+1,272.2091+14.0454%+1,391.6135+16.3910%

Known prime factors:
No known factors for M248851

P-1 results:
 GHz-DaysworthFactor
probability
dateuseridcompidb1b2estagefactordigitsbits*spentsaved
2000-11-25ANONYMOUSv4_computers1000004000000---0.003--2.243%
2001-06-09ANONYMOUSv4_computers10000010000000---0.005--2.710%
2002-06-02ANONYMOUSv4_computers327683276800---0.002--1.551%
2002-08-10ANONYMOUSv4_computers655366553600---0.003--2.232%
2003-03-07ANONYMOUSv4_computers13107213107200---0.007--3.040%
2003-11-08ANONYMOUSv4_computers26214426214400---0.014--3.965%
2011-02-07Jocelyn LaroucheManual testing20000002000000---0.016--2.599%
2011-07-24Jocelyn LaroucheManual testing20167632016763---0.016--2.607%
2012-02-26Jocelyn LaroucheManual testing25209542520954---0.021--2.823%
2013-10-13David Campeaui5-2500k257000074530000---0.053--6.368%
2014-12-24thelegendarymudkipi5-4670k10000000250000000---0.188--8.540%
2016-05-13mognutsManual testing278269550---5.22314e-5--0.136%
2021-12-04Seth_TrManual testing120000000120000000---0.976--7.898%
2021-12-05Seth_TrManual testing12000000057783635910---26.54--17.820%
2022-05-29Sid & AndyRocky2630000002865440107530---1,272--24.198%


P+1 Factoring results:
dateuseridcompidb1b2startfactorSmoothdigitsbits*ghz-days
2023-02-05masserManual testing300000009600000007259--0.775
2023-02-05masserManual testing3000000099000000027--0.788
2023-02-11masserManual testing3000000099000000065--0.788


Trial Factoring results:
 BitsFactorGHz-Daysworth
dateuseridcompidfromtofactorbits*digitsspentsaved
1999-11-24ANONYMOUSv4_computers252253--0.002--
2000-04-27ANONYMOUSv4_computers21254--0.010--
2022-03-07LordJuliusManual testing254255--0.010--
2001-02-18ANONYMOUSv4_computers21256--0.039--
2002-04-14ANONYMOUSv4_computers21257--0.077--
2016-02-23Mark RoseManual testing257258--0.077--
2008-12-31Sturle Sundegluck.ifi258259--0.154--
2009-01-24Sturle Sundekraus.ifi259260--0.309--
2013-07-13lycornasteroid260261--0.617--
2015-08-10snme2pm1Manual testing261262--1.234--
2016-01-27Gordon SpenceManual testing262263--3.945--
2016-01-27Gordon SpenceManual testing263264--7.890--
2018-03-12Gordon SpenceManual testing264265--15.01--
2019-12-31Gordon SpenceManual testing265266--30.03--


ECM factoring results:
Total ECM effort:19.146 GHz-days
Estimated T-Level:29.855
DigitsB1CompleteFacMiss
201100064.1780.000%
25500009.2400.010%
302500000.97137.874%
3510000000.08092.335%
4030000000.00599.468%


ECM Summary

B1B2factorcurvesGHz-days
5000050000002931.751
2500002500000058217.39


Lucas-Lehmer results:
dateuseridcompidres64spent (GHz-days)
1997-01-01Ken Kiefer02A346BFE956DDED0.001
2016-06-01MadPooManual testing02A346BFE956DDED0.001


PRP results:
No PRP results for M248851


P-1 factor-bounds graph:
B1 = 263000000, B2 = 2865440107530 (P-1 stage 2)
B1 = 120000000, B2 = 57783635910 (P-1 stage 2)
B1 = 263000000 (P-1 stage 1)
B1 = 120000000 (P-1 stage 1)
B1 = 10000000, B2 = 250000000 (P-1 stage 2)
B1 = 10000000 (P-1 stage 1)
B1 = 2570000, B2 = 74530000 (P-1 stage 2)
B1 = 2570000 (P-1 stage 1)
B1 = 2520954 (P-1 stage 1)
B1 = 2016763 (P-1 stage 1)
B1 = 2000000 (P-1 stage 1)
B1 = 262144, B2 = 26214400 (P-1 stage 2)
B1 = 131072, B2 = 13107200 (P-1 stage 2)
B1 = 100000, B2 = 10000000 (P-1 stage 2)
B1 = 65536, B2 = 6553600 (P-1 stage 2)
B1 = 100000, B2 = 4000000 (P-1 stage 2)
B1 = 262144 (P-1 stage 1)
B1 = 32768, B2 = 3276800 (P-1 stage 2)
B1 = 131072 (P-1 stage 1)
B1 = 100000 (P-1 stage 1)
B1 = 65536 (P-1 stage 1)
B1 = 32768 (P-1 stage 1)
B1 = 2782, B2 = 69550 (P-1 stage 2)
B1 = 2782 (P-1 stage 1)
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TF factor-bounds graph:
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this exponent TF target: 44
TF double-checked to: 67.8
ECM T-Level=29.85 ~= 83-bit
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Last modified: 2023-04-26T21:34:10+00:00