The number 81432
81432 is a composite number with 64 divisors. Its prime factorisation is × × 13 × 29. Divisors (64): 1, 2, 3, 4, 6, 8, 9, 12, 13, 18, 24, 26, 27, 29, 36, 39 … 81432.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81432: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.
- 2
81432 is composite. Its prime factorisation is
- 3
The divisors add up to 252000; without 81432 itself that is 170568, so 81432 is abundant (170568 is more than 81432). Euler's totient φ(81432) = 24192 numbers up to 81432 share no factor with it.
- 4
The digits of 81432 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 89 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81432 = 2^{3} \times 3^{3} \times 13 \times 29 \]81432 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 64 |
| Sum of divisors | 252000 |
| Euler totient φ(n) | 24192 |
| Square | 6631170624 |
| Cube | 539989486253568 |
| Square root | 285.362927 (= 6√2262) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 89 |
| Scientific notation | 8.1432 × |
81432 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand four hundred and thirty-two |
| Binary (base 2) | 10011111000011000 |
| Octal (base 8) | 237030 |
| Hexadecimal (base 16) | 13E18 |
| Base 3 | 11010201000 |
| As time | 81432 seconds = 22 h 37 min 12 s |
Is 81432 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81432 ÷ 2 = 40716) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81432 ÷ 3 = 27144) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (81432 ÷ 4 = 20358) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (81432 ÷ 6 = 13572) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 (81432 ÷ 8 = 10179) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (81432 ÷ 9 = 9048) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | 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 (81432 ÷ 12 = 6786) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81432 a prime number?
No. 81432 = × × 13 × 29, so it is divisible by 2.
What are the factors of 81432?
1, 2, 3, 4, 6, 8, 9, 12, 13, 18, 24, 26, 27, 29, 36, 39, 52, 54, 58, 72, 78, 87, 104, 108, 116, 117, 156, 174, 216, 232, 234, 261, 312, 348, 351, 377, 468, 522, 696, 702, 754, 783, 936, 1044, 1131, 1404, 1508, 1566, 2088, 2262, 2808, 3016, 3132, 3393, 4524, 6264, 6786, 9048, 10179, 13572, 20358, 27144, 40716, 81432.
What is 81432 in binary?
10011111000011000 (hexadecimal 13E18, octal 237030).
What is the square root of 81432?
About 285.3629, exactly 6√2262.
Is 81432 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 81432?
81432 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.