Let us usual $\omega(n)$ and $\Omega(n)$ denote the number of distinct prime factors and the number of total prime factors of $n$ respectively. Asymptotic formulas for the sum $\underset{2\leq n\leq x} \to \sum n^{-1/\Omega (n)}$ and the logarithm of the sum $\sum\limits{2\leq n\leq x} n^{-1/\omega(n)}$ are derived.