Which one of the numbers 25, 16, 49, 63, 81 is not like the others

63

Step-by-step explanation:

The other numbers are squares.

5 x 5 = 25

4 x 4 = 16

7 x 7 = 49

9 x 9 = 81

A square number or perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself.

Answer: 63

Step-by-step explanation: Unlike the others the square root of 63 is not a whole number. 25 is 5, 16 is 4, 49 is 7, and 81 is 9.