The number 31689
31689 is a composite number with 12 divisors. Its prime factorisation is × 7 × 503. Divisors (12): 1, 3, 7, 9, 21, 63, 503, 1509, 3521, 4527, 10563, 31689.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31689 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31689 is composite. Its prime factorisation is
- 3
The divisors add up to 52416; without 31689 itself that is 20727, so 31689 is deficient (20727 is less than 31689). Euler's totient φ(31689) = 18072 numbers up to 31689 share no factor with it.
- 4
The digits of 31689 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 103 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31689 = 3^{2} \times 7 \times 503 \]31689 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 52416 |
| Euler totient φ(n) | 18072 |
| Square | 1004192721 |
| Cube | 31821863135769 |
| Square root | 178.014044 (= 3√3521) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 103 |
| Scientific notation | 3.1689 × |
31689 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand six hundred and eighty-nine |
| Binary (base 2) | 111101111001001 |
| Octal (base 8) | 75711 |
| Hexadecimal (base 16) | 7BC9 |
| Base 3 | 1121110200 |
| As time | 31689 seconds = 8 h 48 min 9 s |
Is 31689 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 (31689 ÷ 3 = 10563) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (31689 ÷ 7 = 4527) | 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 | Yes (31689 ÷ 9 = 3521) | 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 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 31689 a prime number?
No. 31689 = × 7 × 503, so it is divisible by 3.
What are the factors of 31689?
1, 3, 7, 9, 21, 63, 503, 1509, 3521, 4527, 10563, 31689.
What is 31689 in binary?
111101111001001 (hexadecimal 7BC9, octal 75711).
What is the square root of 31689?
About 178.0140, exactly 3√3521.
Is 31689 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 31689?
It is a composite number with 12 divisors.