Factors of 90
There are 12 factors of 90 — the full list is below, with factor pairs, prime factorization, and divisibility notes.
Factors of 90
1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90
Factor pairs of 90
- 1 × 90
- 2 × 45
- 3 × 30
- 5 × 18
- 6 × 15
- 9 × 10
Prime factorization of 90
90 = 2 × 3² × 5
Number facts
- 90 is a composite number.
- 90 has 12 factors.
- 90 is not a perfect square.
- The sum of all factors of 90 is 234.
Divisibility rules that apply to 90
- 90 is divisible by 2 because it ends in an even digit (0, 2, 4, 6, or 8).
- 90 is divisible by 3 because the sum of its digits (9) is divisible by 3.
- 90 is divisible by 5 because it ends in 0 or 5.
- 90 is divisible by 9 because the sum of its digits (9) is divisible by 9.
- 90 is divisible by 10 because it ends in 0.
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How the factors of 90 are calculated
To find the factors of 90, every whole number from 1 up to the square root of 90(about 9.49) is tested for even division. 90 is even, and it divides evenly by 2, 3, 5, 6, among others. Written as a product of primes, 90 = 2 × 3² × 5, which confirms every factor above is a combination of those prime building blocks.
Frequently asked questions about 90
How many factors does 90 have?
90 has 12 factors: 1, 2, 3, 5, 6, 9, 10, 15, 18, 30, 45, 90.
Is 90 a prime number?
No. 90 is composite because it has factors other than 1 and itself.
What are the factor pairs of 90?
The factor pairs of 90 are 1 × 90, 2 × 45, 3 × 30, 5 × 18, 6 × 15, 9 × 10.
What is the prime factorization of 90?
The prime factorization of 90 is 2 × 3² × 5.