Euler's theorem

For positive integers a and n that are coprime, raising a to the power of Euler's totient φ(n) leaves remainder 1 when divided by n. It is used in modular arithmetic, such as simplifying large powers and in RSA cryptography.

a^{\varphi(n)} \equiv 1 \pmod{n}

What the symbols mean

a positive integer coprime to n
a positive integer modulus
Euler's totient function, the count of integers from 1 to n that are coprime to n

About this formula

  • FieldMathematics
  • TopicNumber theory
  • LevelUniversity
  • Also calledFermat–Euler theorem, Euler's totient theorem, Euler theorem modular arithmetic, generalization of Fermat's little theorem, power congruent to 1 modulo n, totient congruence
  • SourceWikidata Q193910

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