EN
Let ϕ(n) denote the Euler totient function. We study the error term of the general kth Riesz mean of the arithmetical function n/ϕ(n) for any positive integer k ≥ 1, namely the error term $E_k(x)$ where
$1/k! ∑_{n≤x} n/ϕ(n) (1 - n/x)^{k} = M_k(x) + E_k(x)$.
For instance, the upper bound for |E_k(x)| established here improves the earlier known upper bounds for all integers k satisfying $k ≫ (log x)^{1+ϵ}$.