The prime factorization of 36 can be written as 2x2x3x3. Numbers greater than 1 that can only be divided by themselves and 1 are called prime numbers. Each non-prime number has a unique prime factorization.
The best way to find the prime factorization of an even number is to first divide the number by 2. When dividing 36 by 2, the result is 18. This is not a prime number, so further divide by 2 to get 9. The result is now 2x2x9. The number 9 is not a prime and is also not even, so divide by the next prime number, 3. This results in 3. The prime factorization of 36 is now 2x2x3x3, which are all prime numbers.