The number 3825
3825 is a composite number with 18 divisors. Its prime factorisation is × × 17. Divisors (18): 1, 3, 5, 9, 15, 17, 25, 45, 51, 75, 85, 153, 225, 255, 425, 765 … 3825.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
3825 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
3825 is composite. Its prime factorisation is
- 3
The divisors add up to 7254; without 3825 itself that is 3429, so 3825 is deficient (3429 is less than 3825). Euler's totient φ(3825) = 1920 numbers up to 3825 share no factor with it.
- 4
The digits of 3825 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 38 steps to reach 1.
LaTeX source of the formulas on this page
\[ 3825 = 3^{2} \times 5^{2} \times 17 \]3825 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 18 |
| Sum of divisors | 7254 |
| Euler totient φ(n) | 1920 |
| Square | 14630625 |
| Cube | 55962140625 |
| Square root | 61.846584 (= 15√17) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 38 |
| Scientific notation | 3.825 × |
3825 in other forms
| Form | Value |
|---|---|
| In words | three thousand eight hundred and twenty-five |
| Roman numerals | MMMDCCCXXV |
| Binary (base 2) | 111011110001 |
| Octal (base 8) | 7361 |
| Hexadecimal (base 16) | EF1 |
| Base 3 | 12020200 |
| As time | 3825 seconds = 1 h 3 min 45 s |
Is 3825 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 (3825 ÷ 3 = 1275) | 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 (3825 ÷ 5 = 765) | 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 3) | 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 | Yes (3825 ÷ 9 = 425) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 3825 a prime number?
No. 3825 = × × 17, so it is divisible by 3.
What are the factors of 3825?
1, 3, 5, 9, 15, 17, 25, 45, 51, 75, 85, 153, 225, 255, 425, 765, 1275, 3825.
What is 3825 in binary?
111011110001 (hexadecimal EF1, octal 7361).
What is the square root of 3825?
About 61.8466, exactly 15√17.
What is 3825 in Roman numerals?
MMMDCCCXXV.
Is 3825 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 3825?
It is a composite number with 18 divisors.