Pattern Recognition - 35

Find the odd man out.

2,  3  , 7 , 17 , 27

1. 2      2. 3     3. 17    4. 27


Answer

My idea was to have a non-prime number and all others are prime numbers. The odd value is 27.
Prime number   Prime number - Wikipedia, the free encyclopedia

But there is another way of finding the odd value. Except 2, all others are odd numbers. So here the odd man is the even number 2.