Composite Odd Numbers with Examples and FAQs

What are Odd Composite Numbers?

A Composite number is a natural number that has factors other than 1 and itself, i.e., it has more than two factors.

A number that does not have 2 as a factor is odd. Composite Odd numbers are natural numbers that are both odd and composite.

For example, 35 is an odd number as it is not divisible by 2.

Now the factors of 35 are 1, 5, 7, and 35. Hence, 35 has factors that are other than 1 and itself. 35 is an odd composite number.

Properties of odd composite numbers

An odd composite number can be defined as an odd natural number that is a multiple of several smaller natural numbers. The properties of odd composite numbers are:

• They are evenly divisible by smaller numbers, that are either prime or smaller composite than the given number.
• The smaller numbers are also odd numbers. As we know the product of odd numbers is odd.
• Every odd composite number is made up of two or more odd prime numbers. 

List Of Odd Composite Numbers from 1 to 100

9, 15, 21, 25, 27, 33, 35, 39, 45, 49, 51, 55, 57, 63, 65, 69, 75, 77, 81, 85, 87, 91, 93, 95 and 99.

Examples

Example 1: Is 225 an odd composite number or not?

Solution:

The given number is 225. As the digit at the unit’s place is not divisible by 2 hence 2 is not a factor of 225, and hence, 225 is an odd number.

Since the digit at the unit’s place is 5 in 225, therefore, it is divisible by 5.

225 ÷ 5 = 45

45 ÷ 5 = 9

9 ÷ 3 = 3

3 ÷ 3 = 1

Hence the factorisation of 225 is 5 × 5 × 3 × 3. Since 225 has factors other than 1 and itself and 225 is an odd number, we can say that 225 is an odd composite number.

Example 2: What are the first five odd composite numbers? Calculate the sum of the number. Is the sum an odd composite number?

Solution:

The first five odd composite numbers are 9, 15, 21, 25 and 27.

The sum of the numbers = 9 + 15 + 21 + 25 + 27 = 97.

97 is an odd number but it is not divisible by any number other than 1 and itself, hence 97 is not an odd composite number.