The number 42240
42240 is a composite number with 72 divisors. Its prime factorisation is × 3 × 5 × 11. Divisors (72): 1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 15, 16, 20, 22, 24, 30 … 42240.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42240: a Harshad number: divisible by its digit sum 12.
- 2
42240 is composite. Its prime factorisation is
- 3
The divisors add up to 147168; without 42240 itself that is 104928, so 42240 is abundant (104928 is more than 42240). Euler's totient φ(42240) = 10240 numbers up to 42240 share no factor with it.
- 4
The digits of 42240 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 119 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42240 = 2^{8} \times 3 \times 5 \times 11 \]42240 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 72 |
| Sum of divisors | 147168 |
| Euler totient φ(n) | 10240 |
| Square | 1784217600 |
| Cube | 75365351424000 |
| Square root | 205.523721 (= 16√165) |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 119 |
| Scientific notation | 4.224 × |
42240 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand two hundred and forty |
| Binary (base 2) | 1010010100000000 |
| Octal (base 8) | 122400 |
| Hexadecimal (base 16) | A500 |
| Base 3 | 2010221110 |
| As time | 42240 seconds = 11 h 44 min 0 s |
Is 42240 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42240 ÷ 2 = 21120) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (42240 ÷ 3 = 14080) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (42240 ÷ 4 = 10560) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (42240 ÷ 5 = 8448) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (42240 ÷ 6 = 7040) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 (42240 ÷ 8 = 5280) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (42240 ÷ 10 = 4224) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (42240 ÷ 11 = 3840) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (42240 ÷ 12 = 3520) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42240 a prime number?
No. 42240 = × 3 × 5 × 11, so it is divisible by 2.
What are the factors of 42240?
1, 2, 3, 4, 5, 6, 8, 10, 11, 12, 15, 16, 20, 22, 24, 30, 32, 33, 40, 44, 48, 55, 60, 64, 66, 80, 88, 96, 110, 120, 128, 132, 160, 165, 176, 192, 220, 240, 256, 264, 320, 330, 352, 384, 440, 480, 528, 640, 660, 704, 768, 880, 960, 1056, 1280, 1320, 1408, 1760, 1920, 2112, 2640, 2816, 3520, 3840, 4224, 5280, 7040, 8448, 10560, 14080, 21120, 42240.
What is 42240 in binary?
1010010100000000 (hexadecimal A500, octal 122400).
What is the square root of 42240?
About 205.5237, exactly 16√165.
Is 42240 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 42240?
42240 is a Harshad number: divisible by its digit sum 12.