# Carmichael number

> English word · Noun

## Definitions
1. A composite number n that satisfies the modular arithmetic congruence relation bⁿ⁻¹≡1(mod n) for all integers 1<b<n that are relatively prime to n.

## Etymology
Named after Robert Daniel Carmichael (1879–1967), American mathematician.

## Source
Compiled from Wiktionary via kaikki.org (CC BY-SA). Data vintage: 2026-05-06.
Canonical page: https://plainspell.com/en/word/carmichael-number