Is 421 a prime number?
Yes, 421 is a prime number. Its only factors are 1 and 421.
Is 421 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 √421 ≈ 20.52. If none of them divides 421, it is prime.
- 3
None of them divides 421, so it is prime.
Testing 421 by the primes up to its square root
| Prime | Division | Result |
|---|---|---|
| 2 | 421 ÷ 2 | leaves 1 |
| 3 | 421 ÷ 3 | leaves 1 |
| 5 | 421 ÷ 5 | leaves 1 |
| 7 | 421 ÷ 7 | leaves 1 |
| 11 | 421 ÷ 11 | leaves 3 |
| 13 | 421 ÷ 13 | leaves 5 |
| 17 | 421 ÷ 17 | leaves 13 |
| 19 | 421 ÷ 19 | leaves 3 |
Questions
Is 421 a prime number?
Yes, 421 is a prime number. Its only factors are 1 and 421.
What is the next prime after 421?
431.
What is the prime number before 421?
419.
What are the factors of 421?
1, 421.