The number 28809
28809 is a composite number with 16 divisors. Its prime factorisation is × 11 × 97. Divisors (16): 1, 3, 9, 11, 27, 33, 97, 99, 291, 297, 873, 1067, 2619, 3201, 9603, 28809.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28809: a Harshad number: divisible by its digit sum 27.
- 2
28809 is composite. Its prime factorisation is
- 3
The divisors add up to 47040; without 28809 itself that is 18231, so 28809 is deficient (18231 is less than 28809). Euler's totient φ(28809) = 17280 numbers up to 28809 share no factor with it.
- 4
The digits of 28809 add up to 27, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 134 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28809 = 3^{3} \times 11 \times 97 \]28809 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 47040 |
| Euler totient φ(n) | 17280 |
| Square | 829958481 |
| Cube | 23910273879129 |
| Square root | 169.732142 (= 3√3201) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 134 |
| Scientific notation | 2.8809 × |
28809 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand eight hundred and nine |
| Binary (base 2) | 111000010001001 |
| Octal (base 8) | 70211 |
| Hexadecimal (base 16) | 7089 |
| Base 3 | 1110112000 |
| As time | 28809 seconds = 8 h 0 min 9 s |
Is 28809 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 (28809 ÷ 3 = 9603) | 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 | No (remainder 4) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (28809 ÷ 9 = 3201) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (28809 ÷ 11 = 2619) | 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 28809 a prime number?
No. 28809 = × 11 × 97, so it is divisible by 3.
What are the factors of 28809?
1, 3, 9, 11, 27, 33, 97, 99, 291, 297, 873, 1067, 2619, 3201, 9603, 28809.
What is 28809 in binary?
111000010001001 (hexadecimal 7089, octal 70211).
What is the square root of 28809?
About 169.7321, exactly 3√3201.
Is 28809 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 28809?
28809 is a Harshad number: divisible by its digit sum 27.