online calculator for the totient function

(aka Euler’s phi function) for example, φ(10) = 4, because 1, 3, 7, and 9 are relatively prime to 10 Here’s the link. keywords: [mathematics] [relatively prime] [coprime] [relatively-prime] [co-prime] [prime factorization] [multiplicative function] [function-value lookups] [function-evaluation] [function evaluation]