The number 28768
28768 is a composite number with 24 divisors. Its prime factorisation is × 29 × 31. Divisors (24): 1, 2, 4, 8, 16, 29, 31, 32, 58, 62, 116, 124, 232, 248, 464, 496 … 28768.
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How to work it out
- 1
What is special about 28768: a Harshad number: divisible by its digit sum 31.
- 2
28768 is composite. Its prime factorisation is
- 3
The divisors add up to 60480; without 28768 itself that is 31712, so 28768 is abundant (31712 is more than 28768). Euler's totient φ(28768) = 13440 numbers up to 28768 share no factor with it.
- 4
The digits of 28768 add up to 31, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 121 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28768 = 2^{5} \times 29 \times 31 \]28768 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 60480 |
| Euler totient φ(n) | 13440 |
| Square | 827597824 |
| Cube | 23808334200832 |
| Square root | 169.611320 (= 4√1798) |
| Digit sum / digital root | 31 / 4 |
| Collatz steps to 1 | 121 |
| Scientific notation | 2.8768 × |
28768 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand seven hundred and sixty-eight |
| Binary (base 2) | 111000001100000 |
| Octal (base 8) | 70140 |
| Hexadecimal (base 16) | 7060 |
| Base 3 | 1110110111 |
| As time | 28768 seconds = 7 h 59 min 28 s |
Is 28768 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (28768 ÷ 2 = 14384) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (28768 ÷ 4 = 7192) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | 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 | Yes (28768 ÷ 8 = 3596) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28768 a prime number?
No. 28768 = × 29 × 31, so it is divisible by 2.
What are the factors of 28768?
1, 2, 4, 8, 16, 29, 31, 32, 58, 62, 116, 124, 232, 248, 464, 496, 899, 928, 992, 1798, 3596, 7192, 14384, 28768.
What is 28768 in binary?
111000001100000 (hexadecimal 7060, octal 70140).
What is the square root of 28768?
About 169.6113, exactly 4√1798.
Is 28768 divisible by 3?
No. Its digits add up to 31, which is not a multiple of 3.
What is special about the number 28768?
28768 is a Harshad number: divisible by its digit sum 31.