Can you find the odd number in the following?
2716, 4135, 5321 and 7145
2716 is the odd one out.
This is because the rest of the numbers add up to be a prime number.
4 + 1 + 3 + 5 = 13
5 + 3 + 2 + 1 = 11
7 + 1 + 4 + 5 = 17
However, in the case of 2716,
2 + 7 + 1 + 6 = 16 which is not a prime number.
