So, now we know, 5 is a Prime Number ... We look at how to decide whether a natural number is prime or composite by looking for proper factors.The importance of being methodical is emphasised.

19 is a prime number. It can only be divided by 1 and 19 without any remainders. The only factors of 19 are 1 and 19. A number that has more than two factors is called a composite number.