The number 28025
28025 is a composite number with 12 divisors. Its prime factorisation is × 19 × 59. Divisors (12): 1, 5, 19, 25, 59, 95, 295, 475, 1121, 1475, 5605, 28025.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28025: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
28025 is composite. Its prime factorisation is
- 3
The divisors add up to 37200; without 28025 itself that is 9175, so 28025 is deficient (9175 is less than 28025). Euler's totient φ(28025) = 20880 numbers up to 28025 share no factor with it.
- 4
The digits of 28025 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 121 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28025 = 5^{2} \times 19 \times 59 \]28025 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 37200 |
| Euler totient φ(n) | 20880 |
| Square | 785400625 |
| Cube | 22010852515625 |
| Square root | 167.406690 (= 5√1121) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 121 |
| Scientific notation | 2.8025 × |
28025 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand and twenty-five |
| Binary (base 2) | 110110101111001 |
| Octal (base 8) | 66571 |
| Hexadecimal (base 16) | 6D79 |
| Base 3 | 1102102222 |
| As time | 28025 seconds = 7 h 47 min 5 s |
Is 28025 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 | No (remainder 2) | 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 (28025 ÷ 5 = 5605) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28025 a prime number?
No. 28025 = × 19 × 59, so it is divisible by 5.
What are the factors of 28025?
1, 5, 19, 25, 59, 95, 295, 475, 1121, 1475, 5605, 28025.
What is 28025 in binary?
110110101111001 (hexadecimal 6D79, octal 66571).
What is the square root of 28025?
About 167.4067, exactly 5√1121.
Is 28025 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 28025?
28025 is a happy number: repeatedly adding the squares of its digits reaches 1.