The number 31239
31239 is a composite number with 16 divisors. Its prime factorisation is × 13 × 89. Divisors (16): 1, 3, 9, 13, 27, 39, 89, 117, 267, 351, 801, 1157, 2403, 3471, 10413, 31239.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31239 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31239 is composite. Its prime factorisation is
- 3
The divisors add up to 50400; without 31239 itself that is 19161, so 31239 is deficient (19161 is less than 31239). Euler's totient φ(31239) = 19008 numbers up to 31239 share no factor with it.
- 4
The digits of 31239 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 134 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31239 = 3^{3} \times 13 \times 89 \]31239 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 50400 |
| Euler totient φ(n) | 19008 |
| Square | 975875121 |
| Cube | 30485362904919 |
| Square root | 176.745580 (= 3√3471) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 134 |
| Scientific notation | 3.1239 × |
31239 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand two hundred and thirty-nine |
| Binary (base 2) | 111101000000111 |
| Octal (base 8) | 75007 |
| Hexadecimal (base 16) | 7A07 |
| Base 3 | 1120212000 |
| As time | 31239 seconds = 8 h 40 min 39 s |
Is 31239 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 (31239 ÷ 3 = 10413) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | 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 | No (remainder 5) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (31239 ÷ 9 = 3471) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31239 a prime number?
No. 31239 = × 13 × 89, so it is divisible by 3.
What are the factors of 31239?
1, 3, 9, 13, 27, 39, 89, 117, 267, 351, 801, 1157, 2403, 3471, 10413, 31239.
What is 31239 in binary?
111101000000111 (hexadecimal 7A07, octal 75007).
What is the square root of 31239?
About 176.7456, exactly 3√3471.
Is 31239 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 31239?
It is a composite number with 16 divisors.