Euler's theorem - Wikipedia
en.wikipedia.org › wiki › Euler&In 1736, Leonhard Euler published a proof of Fermat's little theorem, which is the restriction of Euler's theorem to the case where n is a prime number. Subsequently, Euler presented other proofs of the theorem, culminating with his paper of 1763, in which he proved a generalization to the case where n is not prime. The converse of Euler's theorem is also true: if the above congruence is true, then a {\displaystyle a} and n {\displaystyle n} must be coprime. The theorem is further generalized by
Euler's Theorem | Brilliant Math & Science Wiki
Euler's theorem is a generalization of Fermat's little theorem dealing with powers of integers modulo positive integers. It arises in applications of elementary number theory, including the theoretical underpinning for the RSA …
Euler's theorem - Wikipedia
https://en.wikipedia.org/wiki/Euler's_theorem1. Euler's theorem can be proven using concepts from the theory of groups: The residue classes modulo n that are coprime to n form a group under multiplication (see the article Multiplicative group of integers modulo n for details). The order of that group is φ(n). Lagrange's theorem states that the order of any subgroup of a finite group divides the order of the entire group, in this case φ(n). If a is any number coprimeto n then a is in one of these residue classes, and its powers a, a …