2+(odd)

2^1391+1

Open composite · C307

NFS Planning

GNFS Murphy estimate: 3.49e-21
SNFS Murphy score: 1.48e-18
Preferred method: SNFS
SNFS possible: Yes
SNFS degree: 6
SNFS skew: 1.42651

Identifiers

Target expression: 2^1391+1
Target link: FactorDB page
Target ID: 1000000000012151415
Target changed: -
Parent query: Same as target
Parent ID: -
Cofactor token: C307
Imported: Jun 03, 2026, 04:29 PM UTC

Raw pmain126 Factorization

(1,13,107) 180137367961349059.602097092517317008121572219.617557073219231014175028802485017.C307

SNFS Polynomial

Polynomial

Degree: 6
Murphy: 1.48e-18
Skew: 1.42651
Selected: Best

n: 1820728914716417232979626396087505384616713800613111719551792494402048072720481820862033565528335244340511075372449417541678823364833509774909544865195126837356327365640986723986776786729548905515569502943014310523279673354508627700485414992792684319644834617103213818491641553603527925860329807066795844843
# 2^1391+1, difficulty: 386.52, skewness: 1.00
# cost: 7.33808e+22, est. time: 34943251.31 GHz days (not accurate yet!)
# Optimized skew: 1.42651 Murphy: 1.48e-18
skew: 1.42651
c6: 1
c5: -1
c4: -5
c3: 4
c2: 6
c1: -3
c0: -1
Y1: -162259276829213363391578010288128
Y0: 26328072917139296674479506920917608079723773850137277813577744385
type: snfs