If gcd(a,n)=1\gcd(a, n) = 1gcd(a,n)=1, which theorem states aϕ(n)≡1(modn)a^{\phi(n)} \equiv 1 \pmod{n}aϕ(n)≡1(modn)?
Fermat's Little Theorem
Euler's Totient Theorem
Chinese Remainder Theorem
Wilson's Theorem