Thirteen does have a square root, and in that sense it is a square number. But thirteen is not a perfect square. There is no integer which, when squared, will give thirteen.
13^2 = 169.
3.60555127546398
No
YES
The number is 7.
It was 1936.
It is 7
Yes
because it can divied by 2
Yes.
Yes, 9 squared = 81.
Because 30 times 30 = 900