20 has 3 factor pairs. Pairs are (1,20), (2,10) and (9,9)
12 has 3 factor pairs and the pairs are (1,12), (2,6) and (3,4).
1 and 3
1 and 3
76 has 3 factor pairs: (1,76), (2,38), (4,19).
12 and 18 have three factor pairs.
The factor pairs of 15 are 1 x 15 and 3 x 5.
The factor pairs of 123 are 1 x 123 and 3 x 41
The factor pairs of 141 are 1 x 141, and 3 x 47.
The factor pairs of 213 are 1 x 213 and 3 x 71.
No.
The factor pairs of 39 are 1 x 39 and 3 x 13