What is the 645th prime number?
The 645th prime number is 4793. The next prime is 4799 (a gap of 6) and the one before is 4789.
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 645th one is 4793.
- 2
4793 is prime because no prime up to ā4793 ā 69.23 divides it.
- 3
The primes are spread thinner as numbers grow: by the prime number theorem the 645th prime is close to 645 Ć ln(645) ā 4173, and here it is 4793.
- 4
4793 has no twin: neither 4791 nor 4795 is prime.
Primes around the 645th
| Position | Prime | Gap from the previous |
|---|---|---|
| 642 | 4783 | 24 |
| 643 | 4787 | 4 |
| 644 | 4789 | 2 |
| 645 | 4793 | 4 |
| 646 | 4799 | 6 |
| 647 | 4801 | 2 |
| 648 | 4813 | 12 |
Questions
What is the 645th prime number?
4793.
Which prime number is 4793?
4793 is the 645th prime number.
What is the sum of the first 645 primes?
1,430,306.