3 and 13
Since 13 is a factor of 39, all of its factors are common.
The factors of 39 are: 1, 3, 13, 39.
1, 3, 13, 39.
1, 3, 13, 39
No. Some proper factors are prime.
The proper factors of 220 are 2,4,5,10,11,20,22,44,55,110
1, 3, 13, 39
If 39 had any even factor then that 39 would be a multiple of an even factor. Therefore, 39 would be a multiple of 2 and so 39 would be even. It is not and so all factors of 39 are odd.
The proper factors of 14 are 1, 2, and 7.
The factors of 97 are 1 and 97. Prime numbers don't have "proper" factors.
"Proper factors" are all of a number's factors except one and the number itself.