143



143 is a special number. If a person is going along a number line, marking each number that is divisible by 2, 3, and so on up to 10, 143 is the first non-prime number that they will not stick a number on.

Not Divisible By

 * 2
 * 3
 * 4
 * 5
 * 6
 * 7
 * 8
 * 9
 * 10

Divisible By
Since the person is not sticking 1 on any numbers except 1 and 10 is the highest number they are sticking on, 143 is the first non-prime number without any numbers on it because of the factors 11 and 13.
 * 1
 * 11
 * 13
 * 143