The number 31729
31729 is a twin prime (31727 and 31729 are both prime) and the 3413th prime number. Its only divisors are 1 and 31729.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31729: a twin prime (31727 and 31729 are both prime); the 3413th prime number.
- 2
31729 is prime, so its only factors are 1 and 31729. It is the 3413th prime; the next prime is 31741 and the one before is 31727.
- 3
The divisors add up to 31730; without 31729 itself that is 1, so 31729 is deficient (1 is less than 31729). Euler's totient φ(31729) = 31728 numbers up to 31729 share no factor with it.
- 4
The digits of 31729 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 103 steps to reach 1.
31729 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 31730 |
| Euler totient φ(n) | 31728 |
| Square | 1006729441 |
| Cube | 31942518433489 |
| Square root | 178.126360 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 103 |
| Scientific notation | 3.1729 × |
31729 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand seven hundred and twenty-nine |
| Binary (base 2) | 111101111110001 |
| Octal (base 8) | 75761 |
| Hexadecimal (base 16) | 7BF1 |
| Base 3 | 1121112011 |
| As time | 31729 seconds = 8 h 48 min 49 s |
Is 31729 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 4) | 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 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | 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 31729 a prime number?
Yes. 31729 is divisible only by 1 and itself.
What are the factors of 31729?
1, 31729.
What is 31729 in binary?
111101111110001 (hexadecimal 7BF1, octal 75761).
What is the square root of 31729?
About 178.1264.
Is 31729 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 31729?
31729 is a twin prime (31727 and 31729 are both prime); the 3413th prime number.