The number 31081
31081 is a twin prime (31079 and 31081 are both prime) and the 3349th prime number. Its only divisors are 1 and 31081.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31081: a twin prime (31079 and 31081 are both prime); the 3349th prime number.
- 2
31081 is prime, so its only factors are 1 and 31081. It is the 3349th prime; the next prime is 31091 and the one before is 31079.
- 3
The divisors add up to 31082; without 31081 itself that is 1, so 31081 is deficient (1 is less than 31081). Euler's totient φ(31081) = 31080 numbers up to 31081 share no factor with it.
- 4
The digits of 31081 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 54 steps to reach 1.
31081 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 31082 |
| Euler totient φ(n) | 31080 |
| Square | 966028561 |
| Cube | 30025133704441 |
| Square root | 176.298043 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 54 |
| Scientific notation | 3.1081 × |
31081 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand and eighty-one |
| Binary (base 2) | 111100101101001 |
| Octal (base 8) | 74551 |
| Hexadecimal (base 16) | 7969 |
| Base 3 | 1120122011 |
| As time | 31081 seconds = 8 h 38 min 1 s |
Is 31081 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 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 1) | 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 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | 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 31081 a prime number?
Yes. 31081 is divisible only by 1 and itself.
What are the factors of 31081?
1, 31081.
What is 31081 in binary?
111100101101001 (hexadecimal 7969, octal 74551).
What is the square root of 31081?
About 176.2980.
Is 31081 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 31081?
31081 is a twin prime (31079 and 31081 are both prime); the 3349th prime number.