The number 311
311 is a twin prime (311 and 313 are both prime) and the 64th prime number. Its only divisors are 1 and 311.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 311: a twin prime (311 and 313 are both prime); the 64th prime number.
- 2
311 is prime, so its only factors are 1 and 311. It is the 64th prime; the next prime is 313 and the one before is 307.
- 3
The divisors add up to 312; without 311 itself that is 1, so 311 is deficient (1 is less than 311). Euler's totient φ(311) = 310 numbers up to 311 share no factor with it.
- 4
The digits of 311 add up to 5, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 86 steps to reach 1.
311 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 312 |
| Euler totient φ(n) | 310 |
| Square | 96721 |
| Cube | 30080231 |
| Square root | 17.635192 |
| Digit sum / digital root | 5 / 5 |
| Collatz steps to 1 | 86 |
| Scientific notation | 3.11 × |
311 in other forms
| Form | Value |
|---|---|
| In words | three hundred and eleven |
| Roman numerals | CCCXI |
| Binary (base 2) | 100110111 |
| Octal (base 8) | 467 |
| Hexadecimal (base 16) | 137 |
| Base 3 | 102112 |
| As time | 311 seconds = 5 min 11 s |
Is 311 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | A number is divisible by 7 if double the last digit and subtract it from the rest: the result is a multiple of 7. |
| 8 | No (remainder 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 311 a prime number?
Yes. 311 is divisible only by 1 and itself.
What are the factors of 311?
1, 311.
What is 311 in binary?
100110111 (hexadecimal 137, octal 467).
What is the square root of 311?
About 17.6352.
What is 311 in Roman numerals?
CCCXI.
Is 311 divisible by 3?
No. Its digits add up to 5, which is not a multiple of 3.
What is special about the number 311?
311 is a twin prime (311 and 313 are both prime); the 64th prime number.