Factors of 63
The factors of 63 are 1, 3, 7, 9, 21, 63. No, 63 is a composite number. Its prime factorization is 3^2 × 7.
Factor pairs of 63
Every factor has a partner that multiplies with it to give 63. Listing pairs from the outside in is the fastest way to find all the factors: once the two numbers in a pair meet in the middle, you have them all.
| Pair | Check |
|---|---|
| 1 and 63 | 1 × 63 = 63 |
| 3 and 21 | 3 × 21 = 63 |
| 7 and 9 | 7 × 9 = 63 |
Prime factorization of 63, step by step
Divide by the smallest prime that goes in evenly, then repeat on the result until you reach 1. The divisors you used are the prime factors.
| Step | Divide | Result |
|---|---|---|
| 1 | 63 ÷ 3 | 21 |
| 2 | 21 ÷ 3 | 7 |
| 3 | 7 ÷ 7 | 1 |
So 63 = 3 × 3 × 7, written compactly as 3^2 × 7.
Divisibility checks for 63
The quick rules a student uses before dividing, applied to 63:
| Divisible by | Rule | For 63 | Result |
|---|---|---|---|
| 2 | last digit is even | last digit 3 | no |
| 3 | digit sum divisible by 3 | digits add to 9 | yes |
| 4 | last two digits divisible by 4 | 63 ÷ 4 | no |
| 5 | last digit is 0 or 5 | last digit 3 | no |
| 6 | divisible by both 2 and 3 | odd, digit sum 9 | no |
| 8 | last three digits divisible by 8 | 63 ÷ 8 | no |
| 9 | digit sum divisible by 9 | digits add to 9 | yes |
| 10 | last digit is 0 | last digit 3 | no |
Frequently Asked Questions
What are the factors of 63?
The factors of 63 are 1, 3, 7, 9, 21, 63.
Is 63 a prime number?
No, 63 is a composite number. Its prime factorization is 3^2 × 7.
How many factors does 63 have?
63 has 6 factors. You can get that count from the prime factorization without listing them: add 1 to each exponent in 3^2 × 7 and multiply -- (2+1) × (1+1) = 6.
Is 63 even or odd?
63 is odd (2 is not a factor).
What is the sum of the factors of 63?
1 + 3 + 7 + 9 + 21 + 63 = 104. Leaving out 63 itself, the proper factors add to 41, less than 63, so 63 is a deficient number.
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