The number 28689
28689 is a composite number with 8 divisors. Its prime factorisation is 3 × 73 × 131. Divisors (8): 1, 3, 73, 131, 219, 393, 9563, 28689.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
28689 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
28689 is composite. Its prime factorisation is
- 3
The divisors add up to 39072; without 28689 itself that is 10383, so 28689 is deficient (10383 is less than 28689). Euler's totient φ(28689) = 18720 numbers up to 28689 share no factor with it.
- 4
The digits of 28689 add up to 33, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 77 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28689 = 3 \times 73 \times 131 \]
28689 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 39072 |
| Euler totient φ(n) | 18720 |
| Square | 823058721 |
| Cube | 23612731646769 |
| Square root | 169.378275 |
| Digit sum / digital root | 33 / 6 |
| Collatz steps to 1 | 77 |
| Scientific notation | 2.8689 × |
28689 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand six hundred and eighty-nine |
| Binary (base 2) | 111000000010001 |
| Octal (base 8) | 70021 |
| Hexadecimal (base 16) | 7011 |
| Base 3 | 1110100120 |
| As time | 28689 seconds = 7 h 58 min 9 s |
Is 28689 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 (28689 ÷ 3 = 9563) | 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 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 | 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 1) | 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 28689 a prime number?
No. 28689 = 3 × 73 × 131, so it is divisible by 3.
What are the factors of 28689?
1, 3, 73, 131, 219, 393, 9563, 28689.
What is 28689 in binary?
111000000010001 (hexadecimal 7011, octal 70021).
What is the square root of 28689?
About 169.3783.
Is 28689 divisible by 3?
Yes. Its digits add up to 33, a multiple of 3.
What is special about the number 28689?
It is a composite number with 8 divisors.