The number 28188
28188 is a composite number with 36 divisors. Its prime factorisation is × × 29. Divisors (36): 1, 2, 3, 4, 6, 9, 12, 18, 27, 29, 36, 54, 58, 81, 87, 108 … 28188.
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How to work it out
- 1
What is special about 28188: a Harshad number: divisible by its digit sum 27.
- 2
28188 is composite. Its prime factorisation is
- 3
The divisors add up to 76440; without 28188 itself that is 48252, so 28188 is abundant (48252 is more than 28188). Euler's totient φ(28188) = 9072 numbers up to 28188 share no factor with it.
- 4
The digits of 28188 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 108 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28188 = 2^{2} \times 3^{5} \times 29 \]28188 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 36 |
| Sum of divisors | 76440 |
| Euler totient φ(n) | 9072 |
| Square | 794563344 |
| Cube | 22397151540672 |
| Square root | 167.892823 (= 18√87) |
| Digit sum / digital root | 27 / 9 |
| Collatz steps to 1 | 108 |
| Scientific notation | 2.8188 × |
28188 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand one hundred and eighty-eight |
| Binary (base 2) | 110111000011100 |
| Octal (base 8) | 67034 |
| Hexadecimal (base 16) | 6E1C |
| Base 3 | 1102200000 |
| As time | 28188 seconds = 7 h 49 min 48 s |
Is 28188 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (28188 ÷ 2 = 14094) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (28188 ÷ 3 = 9396) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (28188 ÷ 4 = 7047) | 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 | Yes (28188 ÷ 6 = 4698) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (28188 ÷ 9 = 3132) | 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 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (28188 ÷ 12 = 2349) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28188 a prime number?
No. 28188 = × × 29, so it is divisible by 2.
What are the factors of 28188?
1, 2, 3, 4, 6, 9, 12, 18, 27, 29, 36, 54, 58, 81, 87, 108, 116, 162, 174, 243, 261, 324, 348, 486, 522, 783, 972, 1044, 1566, 2349, 3132, 4698, 7047, 9396, 14094, 28188.
What is 28188 in binary?
110111000011100 (hexadecimal 6E1C, octal 67034).
What is the square root of 28188?
About 167.8928, exactly 18√87.
Is 28188 divisible by 3?
Yes. Its digits add up to 27, a multiple of 3.
What is special about the number 28188?
28188 is a Harshad number: divisible by its digit sum 27.