All others are squares of prime numbers.

All others are divisible by 17.

This is the only square in the group.

All others are divisible by 13.

Except '44', all are prime numbers.

All others are one less then the cube of a number.

? 272 = 2 + 7 + 2 = 11
210 = 2 + 1 + 0 = 3
240 = 2 + 4 + 0 = 6
304 = 3 + 0 + 4 =7
The sum of digit of all numbers except 240 is a prime number, whereas sum of digits of the number 240 is a non-prime. Hence, it is different from all others.

All others are perfect square of natural number.

All others are divisible by 12.

All others are divisible by 7.