What is the 661st prime number?
The 661st prime number is 4943. The next prime is 4951 (a gap of 8) and the one before is 4937.
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 661st one is 4943.
- 2
4943 is prime because no prime up to ā4943 ā 70.31 divides it.
- 3
The primes are spread thinner as numbers grow: by the prime number theorem the 661st prime is close to 661 Ć ln(661) ā 4292, and here it is 4943.
- 4
4943 has no twin: neither 4941 nor 4945 is prime.
Primes around the 661st
| Position | Prime | Gap from the previous |
|---|---|---|
| 658 | 4931 | 12 |
| 659 | 4933 | 2 |
| 660 | 4937 | 4 |
| 661 | 4943 | 6 |
| 662 | 4951 | 8 |
| 663 | 4957 | 6 |
| 664 | 4967 | 10 |
Questions
What is the 661st prime number?
4943.
Which prime number is 4943?
4943 is the 661st prime number.
What is the sum of the first 661 primes?
1,508,340.