i ,-i and prime numbers

I have been wondering what you get when you do the following sums.

The square root of i

The cube root of i

The square root of -i

The cube root of -i

Also can anyone find the smallest and largest known prime number in which the digits 0,1,2,3,4,5,6,7,8 and 9 are used equally?

And finally can anybody find a number in which the digits' factorials add up to that number.

If someone finds the answer to any of these problems please post back.

Oliver