1 and 13.
Itself and any of its multiples
13
1, 13, 169.
4 goes into 36 evenly, but 13 does not.
1, 13, 37, 481.
1, 3, 13, 39
1, 13, 487, 6331.
Just the number one.
1, 3, 13, 39.
1, 11, 13, 143.
1/13 is the highest number
Each of these numbers will go evenly into 91: 1, 7, 13, 91.