645

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This article is about a particular natural number.|View all articles on particular natural numbers

Summary

Factorization

The number 645 is a square-free number with prime factors 3, 5, and 43:

Properties and families

Property or family Parameter values First few numbers satisfying the property Proof of satisfaction/containment/membership
Poulet number (also called Sarrus number) (Fermat pseudoprime to base 2) third Poulet number 341, 561, 645, 1105, 1387, 1729, 1905, 2047, [SHOW MORE] View list on OEIS , and 28 divides 644, so .