The number 31725
31725 is a composite number with 24 divisors. Its prime factorisation is × × 47. Divisors (24): 1, 3, 5, 9, 15, 25, 27, 45, 47, 75, 135, 141, 225, 235, 423, 675 … 31725.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31725 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31725 is composite. Its prime factorisation is
- 3
The divisors add up to 59520; without 31725 itself that is 27795, so 31725 is deficient (27795 is less than 31725). Euler's totient φ(31725) = 16560 numbers up to 31725 share no factor with it.
- 4
The digits of 31725 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 77 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31725 = 3^{3} \times 5^{2} \times 47 \]31725 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 59520 |
| Euler totient φ(n) | 16560 |
| Square | 1006475625 |
| Cube | 31930439203125 |
| Square root | 178.115131 (= 15√141) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 77 |
| Scientific notation | 3.1725 × |
31725 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand seven hundred and twenty-five |
| Binary (base 2) | 111101111101101 |
| Octal (base 8) | 75755 |
| Hexadecimal (base 16) | 7BED |
| Base 3 | 1121112000 |
| As time | 31725 seconds = 8 h 48 min 45 s |
Is 31725 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 (31725 ÷ 3 = 10575) | 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 (31725 ÷ 5 = 6345) | 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 | Yes (31725 ÷ 9 = 3525) | 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 1) | 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 31725 a prime number?
No. 31725 = × × 47, so it is divisible by 3.
What are the factors of 31725?
1, 3, 5, 9, 15, 25, 27, 45, 47, 75, 135, 141, 225, 235, 423, 675, 705, 1175, 1269, 2115, 3525, 6345, 10575, 31725.
What is 31725 in binary?
111101111101101 (hexadecimal 7BED, octal 75755).
What is the square root of 31725?
About 178.1151, exactly 15√141.
Is 31725 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 31725?
It is a composite number with 24 divisors.