The number 28140
28140 is a composite number with 48 divisors. Its prime factorisation is × 3 × 5 × 7 × 67. Divisors (48): 1, 2, 3, 4, 5, 6, 7, 10, 12, 14, 15, 20, 21, 28, 30, 35 … 28140.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28140: a Harshad number: divisible by its digit sum 15.
- 2
28140 is composite. Its prime factorisation is
- 3
The divisors add up to 91392; without 28140 itself that is 63252, so 28140 is abundant (63252 is more than 28140). Euler's totient φ(28140) = 6336 numbers up to 28140 share no factor with it.
- 4
The digits of 28140 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 108 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28140 = 2^{2} \times 3 \times 5 \times 7 \times 67 \]28140 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 91392 |
| Euler totient φ(n) | 6336 |
| Square | 791859600 |
| Cube | 22282929144000 |
| Square root | 167.749814 (= 2√7035) |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 108 |
| Scientific notation | 2.814 × |
28140 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand one hundred and forty |
| Binary (base 2) | 110110111101100 |
| Octal (base 8) | 66754 |
| Hexadecimal (base 16) | 6DEC |
| Base 3 | 1102121020 |
| As time | 28140 seconds = 7 h 49 min 0 s |
Is 28140 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (28140 ÷ 2 = 14070) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (28140 ÷ 3 = 9380) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (28140 ÷ 4 = 7035) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (28140 ÷ 5 = 5628) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (28140 ÷ 6 = 4690) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (28140 ÷ 7 = 4020) | 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 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (28140 ÷ 10 = 2814) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (28140 ÷ 12 = 2345) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28140 a prime number?
No. 28140 = × 3 × 5 × 7 × 67, so it is divisible by 2.
What are the factors of 28140?
1, 2, 3, 4, 5, 6, 7, 10, 12, 14, 15, 20, 21, 28, 30, 35, 42, 60, 67, 70, 84, 105, 134, 140, 201, 210, 268, 335, 402, 420, 469, 670, 804, 938, 1005, 1340, 1407, 1876, 2010, 2345, 2814, 4020, 4690, 5628, 7035, 9380, 14070, 28140.
What is 28140 in binary?
110110111101100 (hexadecimal 6DEC, octal 66754).
What is the square root of 28140?
About 167.7498, exactly 2√7035.
Is 28140 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 28140?
28140 is a Harshad number: divisible by its digit sum 15.