(102)4 = 108. You multiply in that case
And to find prime factors, easiest way is trial and error, eg:
30758 / 2 = 15379, so 2 is a factor
Now find prime factors of 15379
15379 / 2 = 7644.5, so 2 isnt a factor
15379 / 3 = 5126.33, so 3 isnt a factor
15379 / 5 = 3057.8, so 5 isnt a factor...