If a number can be evenly divided by any other natural number than itself and 1, the number is not prime. The smallest prime number is the number 2.
The opposite of prime numbers are composite numbers, which are those evenly divisible by numbers other than themselves and 1. The smallest composite number is the number 4.
Many numbers can be easily eliminated when determining whether or not they are prime numbers. All multiples of a smaller number cannot be primes. For example, it can be assumed that any even number other than 2 is not prime, as it is divisible by 2 in addition to itself and 1.Learn more about Numbers