The number 20731
20731 is the 2334th prime number. Its only divisors are 1 and 20731.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20731: the 2334th prime number.
- 2
20731 is prime, so its only factors are 1 and 20731. It is the 2334th prime; the next prime is 20743 and the one before is 20719.
- 3
The divisors add up to 20732; without 20731 itself that is 1, so 20731 is deficient (1 is less than 20731). Euler's totient φ(20731) = 20730 numbers up to 20731 share no factor with it.
- 4
The digits of 20731 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 162 steps to reach 1.
20731 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 20732 |
| Euler totient φ(n) | 20730 |
| Square | 429774361 |
| Cube | 8909652277891 |
| Square root | 143.982638 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 162 |
| Scientific notation | 2.0731 × |
20731 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand seven hundred and thirty-one |
| Binary (base 2) | 101000011111011 |
| Octal (base 8) | 50373 |
| Hexadecimal (base 16) | 50FB |
| Base 3 | 1001102211 |
| As time | 20731 seconds = 5 h 45 min 31 s |
Is 20731 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 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20731 a prime number?
Yes. 20731 is divisible only by 1 and itself.
What are the factors of 20731?
1, 20731.
What is 20731 in binary?
101000011111011 (hexadecimal 50FB, octal 50373).
What is the square root of 20731?
About 143.9826.
Is 20731 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 20731?
20731 is the 2334th prime number.