Does this mean that the sum of it's digits equals 29?

i.e if the number was 28,469 then 2+8+4+6+9=29

If this is the case then the answer must be no, as the digital root of n is 2, where the digital root is defined as the number obtained by adding all the digits, then adding the digits of that number, and then continuing until a single-digit number is reached.

For example: suppose x=3,298. So we sum it's digits to get 3+2+9+8=22. We then sum the digits of 22 and arrive at 2+2=4. Therefore we say that the digital root of x is 4.

Now, a perfect square can only have a digital root of 1,4,7 or 9, thus ruling out the n given in the question. Can you see why the digital root of a square number can only equal these values?