131 is already prime. No tree.
131 is a prime number. It is only evenly divisible by itself and one.
1997 is already prime; no tree.
5 x 131
262 = 2 x 131
3,537 = 3 * 3 * 3 * 131 or 33 * 131
51 3,17
350=2x5x5x7
33 11,3
a prime factorization tree
11 x 131 = 1441
50 25,2 5,5,2
97 is already prime; no tree.