What is the 421st prime number?
The 421st prime number is 2909. The next prime is 2917 (a gap of 8) and the one before is 2903.
Position
Pick any whole number from 1 to 10,000.
How to work it out
- 1
List the primes in order: 2, 3, 5, 7, 11, 13, ā¦ The 421st one is 2909.
- 2
2909 is prime because no prime up to ā2909 ā 53.94 divides it.
- 3
The primes are spread thinner as numbers grow: by the prime number theorem the 421st prime is close to 421 Ć ln(421) ā 2544, and here it is 2909.
- 4
2909 has no twin: neither 2907 nor 2911 is prime.
Primes around the 421st
| Position | Prime | Gap from the previous |
|---|---|---|
| 418 | 2887 | 8 |
| 419 | 2897 | 10 |
| 420 | 2903 | 6 |
| 421 | 2909 | 6 |
| 422 | 2917 | 8 |
| 423 | 2927 | 10 |
| 424 | 2939 | 12 |
Questions
What is the 421st prime number?
2909.
Which prime number is 2909?
2909 is the 421st prime number.
What is the sum of the first 421 primes?
567,228.