1 has 1 factor
2 has 2 factors
3 has 2 factors
4 has 3 factors
5 has 2 factors
6 has 4 factors
7 has 2 factors
8 has 4 factors
9 has 3 factors
10 has 4 factors
11 has 2 factors
12 has 6 factors
13 has 2 factors
14 has 4 factors
15 has 4 factors
16 has 5 factors
17 has 2 factors
18 has 6 factors
19 has 2 factors
20 has 6 factors
Sorry if wrong
