2^1387-1

Open composite · C390

NFS Planning

GNFS Murphy estimate: 5.35e-26
SNFS Murphy score: 5.63e-19
Preferred method: SNFS
SNFS possible: Yes
SNFS degree: 7
SNFS skew: 0.86501

Identifiers

Target expression: 2^1387-1
Target link: FactorDB page
Target ID: 1000000000000001387
Target changed: -
Parent query: Same as target
Parent ID: -
Cofactor token: C390
Imported: Jun 03, 2026, 04:29 PM UTC

Raw pmain126 Factorization

(19,73) C390

SNFS Polynomial

Polynomial

Degree: 7
Murphy: 5.63e-19
Skew: 0.86501
Selected: Best

n: 682095545303531840421235924637655495579544145778615559911077847647105999097429270256606493341284081508537791565560264704090341495655975964543118338568593372984742933344694630584290161807899965696480921859592501101919474572063533093119705526981082849892254725215231487308246218758172886023988603556489165851862115209638390378397745475864576319814505788064732137949793016408615192403608338431
# 2^1387-1, difficulty: 417.53, skewness: 1.10
# cost: 4.35227e+23, est. time: 207251044.77 GHz days (not accurate yet!)
# Optimized skew: 0.86501 Murphy: 5.63e-19
skew: 0.86501
c7: 1
c0: -2
Y1: -401734511064747568885490523085290650630550748445698208825344
Y0: 1
type: snfs