For a given number and a divisor. If the prime factors of the divisor can divide a number,then can I say that the divisor will divide a number.
For example - 786
divide by 21
If I break 21 in the prime factors - 3 * 7.
So, if the number is divisible by 3 as well as 7 that means the number can be divided by 21. Here 786 is not divisible by 21 because 7 cannot divide it completely.
Similarly, 42 will be broken as - 3 * 7 *2 -- this means it will not be divisible again. Since 7 couldn't divide it.
Is it a right method?