Prime and composite numbers
All whole numbers (except 0 and 1) have minimum two factors: 1 and itself. Numbers, which aren’t divisible by any numbers except 1 and itself, are called
prime numbers.
Numbers, which have also other factors,
are called
composite numbers.
There is an infinite set of prime numbers. The set of them till 200 is:
47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101,
103, 107, 109, 113, 127, 131, 137, 139, 149, 151,
157, 163, 167, 173, 179, 181, 191, 193, 197, 199.