Find how many three digit perfect cubes is there whose sum of the digits is a perfect square

How many two digits perfect squares are there ?

How many seven-digit numbers are there, the sum of whose digit is even?

mu ={Two digit perfect squases for which sum of digits is a perfect square } Y={Two digit perfect squases for which sum of digits is a perfect square } Find (X cup Y)

Find the least number of three digits which is perfect square.

Find the least number of three digits which is perfect square.

Find the largest number of 3 digits which is a perfect square.

Find the least number of 4 digits which is a perfect square.