There are lots of numbers between 63 and 720. Exactly halfway between them is 391.50, so that may be the answer you are looking for.
It can be, only it is not a perfect square. 72 = 7*7 = 49 and 82 = 8*8 = 64 So 63 lies between the squares of 7 and 8 and so there is no whole number whose square is 63.
There isn't a prime number between 63 and 65
54
If you mean 6 and 3 then they are 5 and 4
The integer / whole number between 63 and 65 is 64. Any number that you can write down that's more than 63 and less than 65 is a rational number between 63 and 65. There are an infinite number of them, including . . . 63.0000000001 63.01 63.1 63.99909990901 64 64.00001 . . etc.
It is: (63+57)/2 = 60
7 and 8
The country lies between latitudes 19° and 28°S, and longitudes 54° and 63°W.
It is: 0.625
It is: 75
The number is 63.
67 or 71