What is the 721st prime number?
The 721st prime number is 5449. The next prime is 5471 (a gap of 22) and the one before is 5443.
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 721st one is 5449.
- 2
5449 is prime because no prime up to ā5449 ā 73.82 divides it.
- 3
The primes are spread thinner as numbers grow: by the prime number theorem the 721st prime is close to 721 Ć ln(721) ā 4745, and here it is 5449.
- 4
5449 has no twin: neither 5447 nor 5451 is prime.
Primes around the 721st
| Position | Prime | Gap from the previous |
|---|---|---|
| 718 | 5437 | 6 |
| 719 | 5441 | 4 |
| 720 | 5443 | 2 |
| 721 | 5449 | 6 |
| 722 | 5471 | 22 |
| 723 | 5477 | 6 |
| 724 | 5479 | 2 |
Questions
What is the 721st prime number?
5449.
Which prime number is 5449?
5449 is the 721st prime number.
What is the sum of the first 721 primes?
1,820,250.