The number 28749
28749 is a composite number with 12 divisors. Its prime factorisation is 3 × 7 × . Divisors (12): 1, 3, 7, 21, 37, 111, 259, 777, 1369, 4107, 9583, 28749.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
28749 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
28749 is composite. Its prime factorisation is
- 3
The divisors add up to 45024; without 28749 itself that is 16275, so 28749 is deficient (16275 is less than 28749). Euler's totient φ(28749) = 15984 numbers up to 28749 share no factor with it.
- 4
The digits of 28749 add up to 30, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 33 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28749 = 3 \times 7 \times 37^{2} \]28749 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 45024 |
| Euler totient φ(n) | 15984 |
| Square | 826505001 |
| Cube | 23761192273749 |
| Square root | 169.555301 (= 37√21) |
| Digit sum / digital root | 30 / 3 |
| Collatz steps to 1 | 33 |
| Scientific notation | 2.8749 × |
28749 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand seven hundred and forty-nine |
| Binary (base 2) | 111000001001101 |
| Octal (base 8) | 70115 |
| Hexadecimal (base 16) | 704D |
| Base 3 | 1110102210 |
| As time | 28749 seconds = 7 h 59 min 9 s |
Is 28749 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 (28749 ÷ 3 = 9583) | 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 | Yes (28749 ÷ 7 = 4107) | 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 3) | 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 6) | 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 28749 a prime number?
No. 28749 = 3 × 7 × , so it is divisible by 3.
What are the factors of 28749?
1, 3, 7, 21, 37, 111, 259, 777, 1369, 4107, 9583, 28749.
What is 28749 in binary?
111000001001101 (hexadecimal 704D, octal 70115).
What is the square root of 28749?
About 169.5553, exactly 37√21.
Is 28749 divisible by 3?
Yes. Its digits add up to 30, a multiple of 3.
What is special about the number 28749?
It is a composite number with 12 divisors.