We know that $A^{23} = 0$. What are the eigenvalues of $A$? 
Let $A$ be an $n \times n$ matrix. We know that $A^{23} = 0$. What are the eigenvalues of $A$?

I think it's just $0$, but I'm not sure. How should I do this problem?

Needless to say that $n\ge 23$ so that $A$ is a nilpotent matrix. What about the eigenvalues of a nilpotent matrix?
