Prime factorization for 125

We note that '125' ends in '5'. So it will divide by '5', which is a Prime number.

Hence

5)125

5)25

5)5 = 1

Keep dividing by any prime number, that will go into the answer, in this case '5'.

So

5 x 5 x 5 = 5^(3) = 125

NB

Any number that ends in '5' or '0' will divide by '5'.

Any number that ends with an EVEN number will divide by '2'.

Any number were the digits sum to '9' will divide by '9'. e.g. 27 ; 2 + 7 = 9

27/9 = 3