Let $\mathbb{N}$ be the D225: Set of natural numbers.
Let $\mathbb{C}$ be the D372: Set of complex numbers.
A D992: Function $f : X \to Y$ is an arithmetic function if and only if

(1)	\begin{equation} X \subseteq \mathbb{N} \end{equation}
(2)	\begin{equation} Y \subseteq \mathbb{C} \end{equation}