9514 1404 393
Explanation:
Anything is categorized by how it matches with the definition of the category.
A composite number is a product of primes. A prime number is divisible only by itself and 1.
If a number has more than one prime factor (even if that is just multiple instances of the same prime factor), it goes into the composite number category. If its only prime factor is itself, it goes into the prime number category.
