The number 81324
81324 is a composite number with 30 divisors. Its prime factorisation is × × 251. Divisors (30): 1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 81, 108, 162, 251, 324 … 81324.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81324: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.
- 2
81324 is composite. Its prime factorisation is
- 3
The divisors add up to 213444; without 81324 itself that is 132120, so 81324 is abundant (132120 is more than 81324). Euler's totient φ(81324) = 27000 numbers up to 81324 share no factor with it.
- 4
The digits of 81324 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 76 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81324 = 2^{2} \times 3^{4} \times 251 \]81324 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 30 |
| Sum of divisors | 213444 |
| Euler totient φ(n) | 27000 |
| Square | 6613592976 |
| Cube | 537843835180224 |
| Square root | 285.173631 (= 18√251) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 76 |
| Scientific notation | 8.1324 × |
81324 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand three hundred and twenty-four |
| Binary (base 2) | 10011110110101100 |
| Octal (base 8) | 236654 |
| Hexadecimal (base 16) | 13DAC |
| Base 3 | 11010120000 |
| As time | 81324 seconds = 22 h 35 min 24 s |
Is 81324 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81324 ÷ 2 = 40662) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81324 ÷ 3 = 27108) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (81324 ÷ 4 = 20331) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (81324 ÷ 6 = 13554) | 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 | No (remainder 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (81324 ÷ 9 = 9036) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (81324 ÷ 12 = 6777) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81324 a prime number?
No. 81324 = × × 251, so it is divisible by 2.
What are the factors of 81324?
1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 81, 108, 162, 251, 324, 502, 753, 1004, 1506, 2259, 3012, 4518, 6777, 9036, 13554, 20331, 27108, 40662, 81324.
What is 81324 in binary?
10011110110101100 (hexadecimal 13DAC, octal 236654).
What is the square root of 81324?
About 285.1736, exactly 18√251.
Is 81324 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 81324?
81324 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.