The number 18240
18240 is a composite number with 56 divisors. Its prime factorisation is × 3 × 5 × 19. Divisors (56): 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 19, 20, 24, 30, 32 … 18240.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 18240: a Harshad number: divisible by its digit sum 15.
- 2
18240 is composite. Its prime factorisation is
- 3
The divisors add up to 60960; without 18240 itself that is 42720, so 18240 is abundant (42720 is more than 18240). Euler's totient φ(18240) = 4608 numbers up to 18240 share no factor with it.
- 4
The digits of 18240 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 110 steps to reach 1.
LaTeX source of the formulas on this page
\[ 18240 = 2^{6} \times 3 \times 5 \times 19 \]18240 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 56 |
| Sum of divisors | 60960 |
| Euler totient φ(n) | 4608 |
| Square | 332697600 |
| Cube | 6068404224000 |
| Square root | 135.055544 (= 8√285) |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 110 |
| Scientific notation | 1.824 × |
18240 in other forms
| Form | Value |
|---|---|
| In words | eighteen thousand two hundred and forty |
| Binary (base 2) | 100011101000000 |
| Octal (base 8) | 43500 |
| Hexadecimal (base 16) | 4740 |
| Base 3 | 221000120 |
| As time | 18240 seconds = 5 h 4 min 0 s |
Is 18240 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (18240 ÷ 2 = 9120) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (18240 ÷ 3 = 6080) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (18240 ÷ 4 = 4560) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (18240 ÷ 5 = 3648) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (18240 ÷ 6 = 3040) | 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 (18240 ÷ 8 = 2280) | 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 (18240 ÷ 10 = 1824) | 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 (18240 ÷ 12 = 1520) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 18240 a prime number?
No. 18240 = × 3 × 5 × 19, so it is divisible by 2.
What are the factors of 18240?
1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 16, 19, 20, 24, 30, 32, 38, 40, 48, 57, 60, 64, 76, 80, 95, 96, 114, 120, 152, 160, 190, 192, 228, 240, 285, 304, 320, 380, 456, 480, 570, 608, 760, 912, 960, 1140, 1216, 1520, 1824, 2280, 3040, 3648, 4560, 6080, 9120, 18240.
What is 18240 in binary?
100011101000000 (hexadecimal 4740, octal 43500).
What is the square root of 18240?
About 135.0555, exactly 8√285.
Is 18240 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 18240?
18240 is a Harshad number: divisible by its digit sum 15.