The number 31181
31181 is a twin prime (31181 and 31183 are both prime) and the 3359th prime number. Its only divisors are 1 and 31181.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31181: a twin prime (31181 and 31183 are both prime); the 3359th prime number.
- 2
31181 is prime, so its only factors are 1 and 31181. It is the 3359th prime; the next prime is 31183 and the one before is 31177.
- 3
The divisors add up to 31182; without 31181 itself that is 1, so 31181 is deficient (1 is less than 31181). Euler's totient φ(31181) = 31180 numbers up to 31181 share no factor with it.
- 4
The digits of 31181 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 147 steps to reach 1.
31181 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 31182 |
| Euler totient φ(n) | 31180 |
| Square | 972254761 |
| Cube | 30315875702741 |
| Square root | 176.581426 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 147 |
| Scientific notation | 3.1181 × |
31181 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand one hundred and eighty-one |
| Binary (base 2) | 111100111001101 |
| Octal (base 8) | 74715 |
| Hexadecimal (base 16) | 79CD |
| Base 3 | 1120202212 |
| As time | 31181 seconds = 8 h 39 min 41 s |
Is 31181 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 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 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 5) | 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 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31181 a prime number?
Yes. 31181 is divisible only by 1 and itself.
What are the factors of 31181?
1, 31181.
What is 31181 in binary?
111100111001101 (hexadecimal 79CD, octal 74715).
What is the square root of 31181?
About 176.5814.
Is 31181 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 31181?
31181 is a twin prime (31181 and 31183 are both prime); the 3359th prime number.