The number 31161
31161 is a composite number with 16 divisors. Its prime factorisation is 3 × 13 × 17 × 47. Divisors (16): 1, 3, 13, 17, 39, 47, 51, 141, 221, 611, 663, 799, 1833, 2397, 10387, 31161.
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How to work it out
- 1
31161 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31161 is composite. Its prime factorisation is
- 3
The divisors add up to 48384; without 31161 itself that is 17223, so 31161 is deficient (17223 is less than 31161). Euler's totient φ(31161) = 17664 numbers up to 31161 share no factor with it.
- 4
The digits of 31161 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 85 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31161 = 3 \times 13 \times 17 \times 47 \]
31161 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 48384 |
| Euler totient φ(n) | 17664 |
| Square | 971007921 |
| Cube | 30257577826281 |
| Square root | 176.524786 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 85 |
| Scientific notation | 3.1161 × |
31161 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand one hundred and sixty-one |
| Binary (base 2) | 111100110111001 |
| Octal (base 8) | 74671 |
| Hexadecimal (base 16) | 79B9 |
| Base 3 | 1120202010 |
| As time | 31161 seconds = 8 h 39 min 21 s |
Is 31161 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 | Yes (31161 ÷ 3 = 10387) | 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 3) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | 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 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31161 a prime number?
No. 31161 = 3 × 13 × 17 × 47, so it is divisible by 3.
What are the factors of 31161?
1, 3, 13, 17, 39, 47, 51, 141, 221, 611, 663, 799, 1833, 2397, 10387, 31161.
What is 31161 in binary?
111100110111001 (hexadecimal 79B9, octal 74671).
What is the square root of 31161?
About 176.5248.
Is 31161 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 31161?
It is a composite number with 16 divisors.