The number 87240
87240 is a composite number with 32 divisors. Its prime factorisation is × 3 × 5 × 727. Divisors (32): 1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120 … 87240.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 87240: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
87240 is composite. Its prime factorisation is
- 3
The divisors add up to 262080; without 87240 itself that is 174840, so 87240 is abundant (174840 is more than 87240). Euler's totient φ(87240) = 23232 numbers up to 87240 share no factor with it.
- 4
The digits of 87240 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 71 steps to reach 1.
LaTeX source of the formulas on this page
\[ 87240 = 2^{3} \times 3 \times 5 \times 727 \]87240 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 262080 |
| Euler totient φ(n) | 23232 |
| Square | 7610817600 |
| Cube | 663967727424000 |
| Square root | 295.364182 (= 2√21810) |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 71 |
| Scientific notation | 8.724 × |
87240 in other forms
| Form | Value |
|---|---|
| In words | eighty-seven thousand two hundred and forty |
| Binary (base 2) | 10101010011001000 |
| Octal (base 8) | 252310 |
| Hexadecimal (base 16) | 154C8 |
| Base 3 | 11102200010 |
| As time | 87240 seconds = 24 h 14 min 0 s |
Is 87240 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (87240 ÷ 2 = 43620) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (87240 ÷ 3 = 29080) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (87240 ÷ 4 = 21810) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (87240 ÷ 5 = 17448) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (87240 ÷ 6 = 14540) | 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 | Yes (87240 ÷ 8 = 10905) | 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 (87240 ÷ 10 = 8724) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (87240 ÷ 12 = 7270) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 87240 a prime number?
No. 87240 = × 3 × 5 × 727, so it is divisible by 2.
What are the factors of 87240?
1, 2, 3, 4, 5, 6, 8, 10, 12, 15, 20, 24, 30, 40, 60, 120, 727, 1454, 2181, 2908, 3635, 4362, 5816, 7270, 8724, 10905, 14540, 17448, 21810, 29080, 43620, 87240.
What is 87240 in binary?
10101010011001000 (hexadecimal 154C8, octal 252310).
What is the square root of 87240?
About 295.3642, exactly 2√21810.
Is 87240 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 87240?
87240 is a happy number: repeatedly adding the squares of its digits reaches 1.