Three.
One
What are the factor strings of 120
At least thirty-six of them.
Factor strings are multiplication sentences. 3 x 3 is a factor string for 9.
23 is prime. No strings.
41 is prime. No strings.
one
There are Two factor trees for 20
20 is a factor of 40, among many other numbers.
A Sitar can have from 18 to 20 strings. Only the strings that go across the frets are played. This would mean that only about 8 strings on the sitar are played at any one time.
37 is prime. Two factors. No strings.
2X26