Prime Factorisation of Composite Numbers

A composite number is a number that can be divided evenly by more numbers than 1 and itself. It is the opposite of a prime number. The number 30 can be evenly divided by 1 2 3 5 6 10 15 and 30, with no remainder. Since 30 cannot be divided by just 1 and 30, it is a composite number.

Is 30 a Composite Number? Yes, since 30 has more than two factors i.e. 1, 2, 3, 5, 6, 10, 15, 30. In other words, 30 is a composite number because 30 has more than 2 factors.

The number 30 is not a prime number because it is possible to express it as a product of prime factors. In other words, 30 can be divided by 1, by itself and at least by 2, 3 and 5. So, 30 is a ‘composite number’.

For example, for 986, you do: 98 – (6 x 5) = 68. Since, 68 is divisible by 17, then 986 is also divisible by 17. However, 876 is not divisible by 17 because 87 – (6 x 5) = 57 and 57 is not divisible by 17.

Since 17 cannot be divided evenly by 2 or 3, we know that 17 is a prime number.

The factors of 17 are 1 and 17. The factors of 11 are 1 and 11. As both the numbers 17 and 11 are prime numbers, the common factor of 17 and 11 is 1.

1 Answer. Prime factors of 57 are 3×19 .

3

Is 59 a prime number or a composite number? 59 has only two factors,1 and 59, hence, it is a prime number.

Factors of 77: 1, 7, 11, 77.