Factorisation[]
Factorization is a process which tries to find divisors except 1 and itself. This can be a problem, if the numbers are bigger than about 100 digits. But it's very easy if the numbers are small. You can factorize 21 in your head, the factorization is 3×7.
Example[]
As an example, let's try to factorize 212. A factorization is easy: 212 = 2 × 106. 106 is not prime so we need to continue to factorize: 212 = 2 × 2× 53. 53 is a prime number, so the factorization is ended, because every number in the factorization is prime. This is the very basic form of Factorisation.
Algorithms[]
There are some algorithms.
The easy one is the trial division. We denote an index as m.
1. To factorize a number n.
2. Calculate the modulo of n / m. In the first iteration m is 2. If it zero, it is a divisor.
3. m is now 1 more than in the last iteration (3,4,5,...)
4. Repeat 2