The number 31875
31875 is a composite number with 20 divisors. Its prime factorisation is 3 × × 17. Divisors (20): 1, 3, 5, 15, 17, 25, 51, 75, 85, 125, 255, 375, 425, 625, 1275, 1875 … 31875.
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How to work it out
- 1
31875 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31875 is composite. Its prime factorisation is
- 3
The divisors add up to 56232; without 31875 itself that is 24357, so 31875 is deficient (24357 is less than 31875). Euler's totient φ(31875) = 16000 numbers up to 31875 share no factor with it.
- 4
The digits of 31875 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 54 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31875 = 3 \times 5^{4} \times 17 \]31875 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 56232 |
| Euler totient φ(n) | 16000 |
| Square | 1016015625 |
| Cube | 32385498046875 |
| Square root | 178.535711 (= 25√51) |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 54 |
| Scientific notation | 3.1875 × |
31875 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand eight hundred and seventy-five |
| Binary (base 2) | 111110010000011 |
| Octal (base 8) | 76203 |
| Hexadecimal (base 16) | 7C83 |
| Base 3 | 1121201120 |
| As time | 31875 seconds = 8 h 51 min 15 s |
Is 31875 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 (31875 ÷ 3 = 10625) | 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 | Yes (31875 ÷ 5 = 6375) | 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 4) | 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 3) | 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 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | 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 31875 a prime number?
No. 31875 = 3 × × 17, so it is divisible by 3.
What are the factors of 31875?
1, 3, 5, 15, 17, 25, 51, 75, 85, 125, 255, 375, 425, 625, 1275, 1875, 2125, 6375, 10625, 31875.
What is 31875 in binary?
111110010000011 (hexadecimal 7C83, octal 76203).
What is the square root of 31875?
About 178.5357, exactly 25√51.
Is 31875 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 31875?
It is a composite number with 20 divisors.