The number 31485
31485 is a composite number with 8 divisors. Its prime factorisation is 3 × 5 × 2099. Divisors (8): 1, 3, 5, 15, 2099, 6297, 10495, 31485.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31485 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31485 is composite. Its prime factorisation is
- 3
The divisors add up to 50400; without 31485 itself that is 18915, so 31485 is deficient (18915 is less than 31485). Euler's totient φ(31485) = 16784 numbers up to 31485 share no factor with it.
- 4
The digits of 31485 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 85 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31485 = 3 \times 5 \times 2099 \]
31485 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 50400 |
| Euler totient φ(n) | 16784 |
| Square | 991305225 |
| Cube | 31211245009125 |
| Square root | 177.440131 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 85 |
| Scientific notation | 3.1485 × |
31485 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand four hundred and eighty-five |
| Binary (base 2) | 111101011111101 |
| Octal (base 8) | 75375 |
| Hexadecimal (base 16) | 7AFD |
| Base 3 | 1121012010 |
| As time | 31485 seconds = 8 h 44 min 45 s |
Is 31485 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 (31485 ÷ 3 = 10495) | 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 (31485 ÷ 5 = 6297) | 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 6) | 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 3) | 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 3) | 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 31485 a prime number?
No. 31485 = 3 × 5 × 2099, so it is divisible by 3.
What are the factors of 31485?
1, 3, 5, 15, 2099, 6297, 10495, 31485.
What is 31485 in binary?
111101011111101 (hexadecimal 7AFD, octal 75375).
What is the square root of 31485?
About 177.4401.
Is 31485 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 31485?
It is a composite number with 8 divisors.