Is 1921 a prime number?
No, 1921 is not a prime number. It is divisible by 17: 1921 = 17 × 113.
Is 1921 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 √1921 ≈ 43.83. If none of them divides 1921, it is prime.
- 3
17 divides 1921 exactly, so it is not prime. Its prime factorisation is
LaTeX source of the formulas on this page
\[ 1921 = 17 \times 113 \]
Testing 1921 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 1921 ÷ 2 | leaves 1 |
| 3 | 1921 ÷ 3 | leaves 1 |
| 5 | 1921 ÷ 5 | leaves 1 |
| 7 | 1921 ÷ 7 | leaves 3 |
| 11 | 1921 ÷ 11 | leaves 7 |
| 13 | 1921 ÷ 13 | leaves 10 |
| 17 | 1921 ÷ 17 | divides exactly (113) |
| 19 | 1921 ÷ 19 | leaves 2 |
| 23 | 1921 ÷ 23 | leaves 12 |
| 29 | 1921 ÷ 29 | leaves 7 |
| 31 | 1921 ÷ 31 | leaves 30 |
| 37 | 1921 ÷ 37 | leaves 34 |
Questions
Is 1921 a prime number?
No, 1921 is not a prime number. It is divisible by 17: 1921 = 17 × 113.
What is the next prime after 1921?
1931.
What is the prime number before 1921?
1913.
What are the factors of 1921?
1, 17, 113, 1921.