##### Explanation :

First we will add the digits of every number i.e.

12439 : 1 + 2 + 3 + 4 + 9 = 19

23549 : 2 + 3 + 5 + 4 + 9 = 23

34659 : 3 + 4 + 6 + 5 + 9 = 27

45769 : 4 + 5 + 7 + 6 + 9 = 31

As we can see that in every case the sum of digits of number is a prime number except in case of 34659.

Hence, 34659 is wrong number in the given series.