#### Answer

Complex and pure imaginary.

#### Work Step by Step

Rewrite the radical, by splitting the $\sqrt{-1}$, which is equal to i.
$\sqrt{-36}=\sqrt{-1}\times\sqrt{36}=6i$
The number is complex because it takes on the form a+bi, a=0, and b=6, where a and b are both real numbers.
The number is also real because $b=0$.