The number 28509
28509 is a composite number with 16 divisors. Its prime factorisation is 3 × 13 × 17 × 43. Divisors (16): 1, 3, 13, 17, 39, 43, 51, 129, 221, 559, 663, 731, 1677, 2193, 9503, 28509.
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How to work it out
- 1
28509 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
28509 is composite. Its prime factorisation is
- 3
The divisors add up to 44352; without 28509 itself that is 15843, so 28509 is deficient (15843 is less than 28509). Euler's totient φ(28509) = 16128 numbers up to 28509 share no factor with it.
- 4
The digits of 28509 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 165 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28509 = 3 \times 13 \times 17 \times 43 \]
28509 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 44352 |
| Euler totient φ(n) | 16128 |
| Square | 812763081 |
| Cube | 23171062676229 |
| Square root | 168.846084 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 165 |
| Scientific notation | 2.8509 × |
28509 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand five hundred and nine |
| Binary (base 2) | 110111101011101 |
| Octal (base 8) | 67535 |
| Hexadecimal (base 16) | 6F5D |
| Base 3 | 1110002220 |
| As time | 28509 seconds = 7 h 55 min 9 s |
Is 28509 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 (28509 ÷ 3 = 9503) | 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 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | 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 | 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 28509 a prime number?
No. 28509 = 3 × 13 × 17 × 43, so it is divisible by 3.
What are the factors of 28509?
1, 3, 13, 17, 39, 43, 51, 129, 221, 559, 663, 731, 1677, 2193, 9503, 28509.
What is 28509 in binary?
110111101011101 (hexadecimal 6F5D, octal 67535).
What is the square root of 28509?
About 168.8461.
Is 28509 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 28509?
It is a composite number with 16 divisors.