The number 31986
31986 is a composite number with 12 divisors. Its prime factorisation is 2 × × 1777. Divisors (12): 1, 2, 3, 6, 9, 18, 1777, 3554, 5331, 10662, 15993, 31986.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31986 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31986 is composite. Its prime factorisation is
- 3
The divisors add up to 69342; without 31986 itself that is 37356, so 31986 is abundant (37356 is more than 31986). Euler's totient φ(31986) = 10656 numbers up to 31986 share no factor with it.
- 4
The digits of 31986 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 191 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31986 = 2 \times 3^{2} \times 1777 \]31986 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 69342 |
| Euler totient φ(n) | 10656 |
| Square | 1023104196 |
| Cube | 32725010813256 |
| Square root | 178.846303 (= 3√3554) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 191 |
| Scientific notation | 3.1986 × |
31986 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and eighty-six |
| Binary (base 2) | 111110011110010 |
| Octal (base 8) | 76362 |
| Hexadecimal (base 16) | 7CF2 |
| Base 3 | 1121212200 |
| As time | 31986 seconds = 8 h 53 min 6 s |
Is 31986 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31986 ÷ 2 = 15993) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (31986 ÷ 3 = 10662) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | 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 | Yes (31986 ÷ 6 = 5331) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (31986 ÷ 9 = 3554) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 6) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31986 a prime number?
No. 31986 = 2 × × 1777, so it is divisible by 2.
What are the factors of 31986?
1, 2, 3, 6, 9, 18, 1777, 3554, 5331, 10662, 15993, 31986.
What is 31986 in binary?
111110011110010 (hexadecimal 7CF2, octal 76362).
What is the square root of 31986?
About 178.8463, exactly 3√3554.
Is 31986 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 31986?
It is a composite number with 12 divisors.