Euler's totient function

Named after Swiss mathematician Leonhard Euler (1707–1783).

Euler's totient function

1. (number theory) The function that calculates the total number of integers below a given integer that are coprime to it.

• Usually denoted with the Greek letter phi (${\displaystyle \phi }$ or ${\displaystyle \varphi }$).

• Euler's formula

• Euler's totient function on Wikipedia.Wikipedia