 If "s" > 0,

Setting "s" = 1 gives

If the Riemann hypothesis is true, and formula_52

"d"("n") = σ0("n") is the number of divisors of "n", including 1 and "n" itself.where γ = 0.5772... is the Euler–Mascheroni constant.Euler's totient function φ("n") is the number of positive integers less than "n" and coprime to "n".