The number 28971
28971 is a composite number with 16 divisors. Its prime factorisation is × 29 × 37. Divisors (16): 1, 3, 9, 27, 29, 37, 87, 111, 261, 333, 783, 999, 1073, 3219, 9657, 28971.
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How to work it out
- 1
What is special about 28971: a Harshad number: divisible by its digit sum 27.
- 2
28971 is composite. Its prime factorisation is
- 3
The divisors add up to 45600; without 28971 itself that is 16629, so 28971 is deficient (16629 is less than 28971). Euler's totient φ(28971) = 18144 numbers up to 28971 share no factor with it.
- 4
The digits of 28971 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 103 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28971 = 3^{3} \times 29 \times 37 \]28971 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 45600 |
| Euler totient φ(n) | 18144 |
| Square | 839318841 |
| Cube | 24315906142611 |
| Square root | 170.208695 (= 3√3219) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 103 |
| Scientific notation | 2.8971 × |
28971 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand nine hundred and seventy-one |
| Binary (base 2) | 111000100101011 |
| Octal (base 8) | 70453 |
| Hexadecimal (base 16) | 712B |
| Base 3 | 1110202000 |
| As time | 28971 seconds = 8 h 2 min 51 s |
Is 28971 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 (28971 ÷ 3 = 9657) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (28971 ÷ 9 = 3219) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | 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 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28971 a prime number?
No. 28971 = × 29 × 37, so it is divisible by 3.
What are the factors of 28971?
1, 3, 9, 27, 29, 37, 87, 111, 261, 333, 783, 999, 1073, 3219, 9657, 28971.
What is 28971 in binary?
111000100101011 (hexadecimal 712B, octal 70453).
What is the square root of 28971?
About 170.2087, exactly 3√3219.
Is 28971 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 28971?
28971 is a Harshad number: divisible by its digit sum 27.