The number 31389
31389 is a composite number with 4 divisors. Its prime factorisation is 3 × 10463. Divisors (4): 1, 3, 10463, 31389.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31389: a semiprime: 3 × 10463, the product of two primes.
- 2
31389 is composite. Its prime factorisation is
- 3
The divisors add up to 41856; without 31389 itself that is 10467, so 31389 is deficient (10467 is less than 31389). Euler's totient φ(31389) = 20924 numbers up to 31389 share no factor with it.
- 4
The digits of 31389 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 129 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31389 = 3 \times 10463 \]
31389 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 41856 |
| Euler totient φ(n) | 20924 |
| Square | 985269321 |
| Cube | 30926618716869 |
| Square root | 177.169410 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 129 |
| Scientific notation | 3.1389 × |
31389 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand three hundred and eighty-nine |
| Binary (base 2) | 111101010011101 |
| Octal (base 8) | 75235 |
| Hexadecimal (base 16) | 7A9D |
| Base 3 | 1121001120 |
| As time | 31389 seconds = 8 h 43 min 9 s |
Is 31389 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 (31389 ÷ 3 = 10463) | 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 | No (remainder 1) | 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 6) | 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 6) | 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 31389 a prime number?
No. 31389 = 3 × 10463, so it is divisible by 3.
What are the factors of 31389?
1, 3, 10463, 31389.
What is 31389 in binary?
111101010011101 (hexadecimal 7A9D, octal 75235).
What is the square root of 31389?
About 177.1694.
Is 31389 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 31389?
31389 is a semiprime: 3 × 10463, the product of two primes.