7^421-1

Open composite · C305

NFS Planning

GNFS Murphy estimate: 4.56e-21
SNFS Murphy score: 6.71e-17
Preferred method: SNFS
SNFS possible: Yes
SNFS degree: 7
SNFS skew: 1.04756

Identifiers

Target expression: 7^421-1
Target link: FactorDB page
Target ID: 1000000000018628539
Target changed: -
Parent query: Same as target
Parent ID: -
Cofactor token: C305
Imported: Jun 03, 2026, 04:31 PM UTC

Raw pmain126 Factorization

(1) 120298224779693.1169407471026387018305554817094515359. C305

SNFS Polynomial

Polynomial

Degree: 7
Murphy: 6.71e-17
Skew: 1.04756
Selected: Best

n: 72426669178272279529557301635748367969737413899910907133089592176125360612434918904204991128185741371227575813773691468370399895603467812085996760531941694878594500440579455091751537583468338090871233932271341232926824195917290063570863081411135981560396750518439646469437603313754868901900942811814659723
# 7^421-1, difficulty: 355.79, skewness: 1.32
# cost: 1.15182e+22, est. time: 5484867.23 GHz days (not accurate yet!)
# Optimized skew: 1.04756 Murphy: 6.71e-17
skew: 1.04756
c7: 1
c0: -7
Y1: -508021860739623365322188197652216501772434524836001
Y0: 1
type: snfs