Answer
The series is absolutely convergent.
Work Step by Step
Ratio Test: $\lim\limits_{n \to \infty}|\dfrac{a_{n+1}}{a_{n}}|=\lim\limits_{n \to \infty}|\dfrac{\frac{(n+1)!}{(n+1)^{n}}}{\frac{n!}{n^{n}}}|$
$=\lim\limits_{n \to \infty}|[\frac{n}{n+1}]^{n}|$
$=\lim\limits_{n \to \infty}|[\frac{1}{1+1/n}]^{n}|$
$=\frac{1}{e}\lt 1$
The series is absolutely convergent.