The number 15825
15825 is a composite number with 12 divisors. Its prime factorisation is 3 × × 211. Divisors (12): 1, 3, 5, 15, 25, 75, 211, 633, 1055, 3165, 5275, 15825.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
15825 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
15825 is composite. Its prime factorisation is
- 3
The divisors add up to 26288; without 15825 itself that is 10463, so 15825 is deficient (10463 is less than 15825). Euler's totient φ(15825) = 8400 numbers up to 15825 share no factor with it.
- 4
The digits of 15825 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 146 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15825 = 3 \times 5^{2} \times 211 \]15825 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 26288 |
| Euler totient φ(n) | 8400 |
| Square | 250430625 |
| Cube | 3963064640625 |
| Square root | 125.797456 (= 5√633) |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 146 |
| Scientific notation | 1.5825 × |
15825 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand eight hundred and twenty-five |
| Binary (base 2) | 11110111010001 |
| Octal (base 8) | 36721 |
| Hexadecimal (base 16) | 3DD1 |
| Base 3 | 210201010 |
| As time | 15825 seconds = 4 h 23 min 45 s |
Is 15825 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 (15825 ÷ 3 = 5275) | 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 (15825 ÷ 5 = 3165) | 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 5) | 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 1) | 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 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 15825 a prime number?
No. 15825 = 3 × × 211, so it is divisible by 3.
What are the factors of 15825?
1, 3, 5, 15, 25, 75, 211, 633, 1055, 3165, 5275, 15825.
What is 15825 in binary?
11110111010001 (hexadecimal 3DD1, octal 36721).
What is the square root of 15825?
About 125.7975, exactly 5√633.
Is 15825 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 15825?
It is a composite number with 12 divisors.