What are all the factors of 45? How to find the factors of number 45? Is 45 a prime or a composit number?
asked in Basic Math by expert

1 Answer

The number 45 has 6 factors.

The factors of 45 are: 45, 15, 9, 5, 3, 1

The square root of 45 rounded up to the nearest integer is 7. This is the limit to test our divisions because any number greater than 7 times 7 is greater than 45. So, we stop at 7.

Let's test the values 1 through 7 for division into 45.

  • 45÷1 = 45. Remainder = 0. So, 45 and 1 are factors.
  • 45÷2 = 22. Remainder = 1. So, 22 isn't a factor.
  • 45÷3 = 15. Remainder = 0. So, 15 and 3 are factors.
  • 45÷4 = 11. Remainder = 1. So, 11 isn't a factor.
  • 45÷5 = 9. Remainder = 0. So, 9 and 5 are factors.
  • 45÷6 = 7. Remainder = 3. So, 7 isn't a factor.
  • 45÷7 = 6. Remainder = 3. So, 6 isn't a factor.

Factors of a number n are numbers that can divide n without remainder, ie, remainder = 0. So, choosing only the numbers that meet this criteria from the list above, we find that the numbers which divide 45 (including 45) with no remainder are: 45, 15, 9, 5, 3, 1.

So, the factors of the number 45 are: 45, 15, 9, 5, 3, 1.

A composite number has more than two factors. A prime number has only two factors: 1 and itself. The number 1 is neither prime nor composite.

Because the number 45 has 6 factors, it is termed a composite number in mathematics.

As 45 is a composite number, we can factorize it, ie, express it in prime Factors as follows.

By factorizing 45 we get: 45 = 3 × 3 × 5.

Ie, 45 can be expressed as a product (factor string) of prime numbers (3 × 3 × 5).

answered by questiun