One.
1 and 73
(73,1)
Sixteen factor pairs.
2 factor pairs
1 x 2263, 31 x 73, 73 x 31, 2263 x 1
There are 3 factor pairs of 16.
Three factor pairs
30 has four factor pairs:30,115,210,36,5
225 has five factor pairs:225,175,345,525,915,15
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).