Factors of 11
The factors of 11 are 1, 11. Yes, 11 is a prime number. Its only factors are 1 and 11.
Factor pairs of 11
Every factor has a partner that multiplies with it to give 11. 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 11 | 1 × 11 = 11 |
Prime factorization of 11, step by step
11 is prime, so the ladder is one rung: nothing smaller than 11 divides it except 1. To confirm, you only need to test primes up to √11 ≈ 3: 11 ÷ 2 leaves 1; 11 ÷ 3 leaves 2.
Divisibility checks for 11
The quick rules a student uses before dividing, applied to 11:
| Divisible by | Rule | For 11 | Result |
|---|---|---|---|
| 2 | last digit is even | last digit 1 | no |
| 3 | digit sum divisible by 3 | digits add to 2 | no |
| 4 | last two digits divisible by 4 | 11 ÷ 4 | no |
| 5 | last digit is 0 or 5 | last digit 1 | no |
| 6 | divisible by both 2 and 3 | odd, digit sum 2 | no |
| 8 | last three digits divisible by 8 | 11 ÷ 8 | no |
| 9 | digit sum divisible by 9 | digits add to 2 | no |
| 10 | last digit is 0 | last digit 1 | no |
Frequently Asked Questions
What are the factors of 11?
The factors of 11 are 1, 11.
Is 11 a prime number?
Yes, 11 is a prime number. Its only factors are 1 and 11.
How many factors does 11 have?
11 has 2 factors.
Is 11 even or odd?
11 is odd (2 is not a factor).
What is the sum of the factors of 11?
1 + 11 = 12. Leaving out 11 itself, the proper factors add to 1, less than 11, so 11 is a deficient number.
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