Is 921 a prime number?
No, 921 is not a prime number. It is divisible by 3: 921 = 3 × 307.
Is 921 prime?
Pick any whole number from 1 to 10,000.
How to work it out
- 1
A prime number has exactly two factors: 1 and itself.
- 2
It is enough to test the primes up to √921 ≈ 30.35. If none of them divides 921, it is prime.
- 3
3 divides 921 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 921 = 3 \times 307 \]
Testing 921 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 921 ÷ 2 | leaves 1 |
| 3 | 921 ÷ 3 | divides exactly (307) |
| 5 | 921 ÷ 5 | leaves 1 |
| 7 | 921 ÷ 7 | leaves 4 |
| 11 | 921 ÷ 11 | leaves 8 |
| 13 | 921 ÷ 13 | leaves 11 |
| 17 | 921 ÷ 17 | leaves 3 |
| 19 | 921 ÷ 19 | leaves 9 |
| 23 | 921 ÷ 23 | leaves 1 |
| 29 | 921 ÷ 29 | leaves 22 |
Questions
Is 921 a prime number?
No, 921 is not a prime number. It is divisible by 3: 921 = 3 × 307.
What is the next prime after 921?
929.
What is the prime number before 921?
919.
What are the factors of 921?
1, 3, 307, 921.