factor – factor numbers

Print the prime factors of each specified integer NUMBER.

$factor 2
2: 2
$factor 3
3: 3
$factor 4
4: 2 2
$factor 5
5: 5
$factor 6
6: 2 3
$factor 7
7: 7
$factor 8
8: 2 2 2
$factor 9
9: 3 3
$factor 10
10: 2 5
$factor 11
11: 11
$factor 12
12: 2 2 3
$factor 13
13: 13
$factor 14
14: 2 7
$factor 
15
15: 3 5
$

Prime factor