The number 31393
31393 is a twin prime (31391 and 31393 are both prime) and the 3384th prime number. Its only divisors are 1 and 31393.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31393: a twin prime (31391 and 31393 are both prime); the 3384th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
31393 is prime, so its only factors are 1 and 31393. It is the 3384th prime; the next prime is 31397 and the one before is 31391.
- 3
The divisors add up to 31394; without 31393 itself that is 1, so 31393 is deficient (1 is less than 31393). Euler's totient φ(31393) = 31392 numbers up to 31393 share no factor with it.
- 4
The digits of 31393 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 134 steps to reach 1.
31393 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 31394 |
| Euler totient φ(n) | 31392 |
| Square | 985520449 |
| Cube | 30938443455457 |
| Square root | 177.180699 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 134 |
| Scientific notation | 3.1393 × |
31393 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand three hundred and ninety-three |
| Binary (base 2) | 111101010100001 |
| Octal (base 8) | 75241 |
| Hexadecimal (base 16) | 7AA1 |
| Base 3 | 1121001201 |
| As time | 31393 seconds = 8 h 43 min 13 s |
Is 31393 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 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31393 a prime number?
Yes. 31393 is divisible only by 1 and itself.
What are the factors of 31393?
1, 31393.
What is 31393 in binary?
111101010100001 (hexadecimal 7AA1, octal 75241).
What is the square root of 31393?
About 177.1807.
Is 31393 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 31393?
31393 is a twin prime (31391 and 31393 are both prime); the 3384th prime number; a happy number: repeatedly adding the squares of its digits reaches 1.