The number 81442
81442 is a composite number with 8 divisors. Its prime factorisation is 2 × 43 × 947. Divisors (8): 1, 2, 43, 86, 947, 1894, 40721, 81442.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
81442 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81442 is composite. Its prime factorisation is
- 3
The divisors add up to 125136; without 81442 itself that is 43694, so 81442 is deficient (43694 is less than 81442). Euler's totient φ(81442) = 39732 numbers up to 81442 share no factor with it.
- 4
The digits of 81442 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 89 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81442 = 2 \times 43 \times 947 \]
81442 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 125136 |
| Euler totient φ(n) | 39732 |
| Square | 6632799364 |
| Cube | 540188445802888 |
| Square root | 285.380448 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 89 |
| Scientific notation | 8.1442 × |
81442 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand four hundred and forty-two |
| Binary (base 2) | 10011111000100010 |
| Octal (base 8) | 237042 |
| Hexadecimal (base 16) | 13E22 |
| Base 3 | 11010201101 |
| As time | 81442 seconds = 22 h 37 min 22 s |
Is 81442 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81442 ÷ 2 = 40721) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | 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 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | 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 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81442 a prime number?
No. 81442 = 2 × 43 × 947, so it is divisible by 2.
What are the factors of 81442?
1, 2, 43, 86, 947, 1894, 40721, 81442.
What is 81442 in binary?
10011111000100010 (hexadecimal 13E22, octal 237042).
What is the square root of 81442?
About 285.3804.
Is 81442 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 81442?
It is a composite number with 8 divisors.