The number 31005
31005 is a composite number with 24 divisors. Its prime factorisation is × 5 × 13 × 53. Divisors (24): 1, 3, 5, 9, 13, 15, 39, 45, 53, 65, 117, 159, 195, 265, 477, 585 … 31005.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31005: a Harshad number: divisible by its digit sum 9.
- 2
31005 is composite. Its prime factorisation is
- 3
The divisors add up to 58968; without 31005 itself that is 27963, so 31005 is deficient (27963 is less than 31005). Euler's totient φ(31005) = 14976 numbers up to 31005 share no factor with it.
- 4
The digits of 31005 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 178 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31005 = 3^{2} \times 5 \times 13 \times 53 \]31005 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 58968 |
| Euler totient φ(n) | 14976 |
| Square | 961310025 |
| Cube | 29805417325125 |
| Square root | 176.082367 (= 3√3445) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 178 |
| Scientific notation | 3.1005 × |
31005 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand and five |
| Binary (base 2) | 111100100011101 |
| Octal (base 8) | 74435 |
| Hexadecimal (base 16) | 791D |
| Base 3 | 1120112100 |
| As time | 31005 seconds = 8 h 36 min 45 s |
Is 31005 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 (31005 ÷ 3 = 10335) | 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 | Yes (31005 ÷ 5 = 6201) | 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 2) | 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 | Yes (31005 ÷ 9 = 3445) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | 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 31005 a prime number?
No. 31005 = × 5 × 13 × 53, so it is divisible by 3.
What are the factors of 31005?
1, 3, 5, 9, 13, 15, 39, 45, 53, 65, 117, 159, 195, 265, 477, 585, 689, 795, 2067, 2385, 3445, 6201, 10335, 31005.
What is 31005 in binary?
111100100011101 (hexadecimal 791D, octal 74435).
What is the square root of 31005?
About 176.0824, exactly 3√3445.
Is 31005 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 31005?
31005 is a Harshad number: divisible by its digit sum 9.