The number 81742
81742 is a composite number with 8 divisors. Its prime factorisation is 2 × 23 × 1777. Divisors (8): 1, 2, 23, 46, 1777, 3554, 40871, 81742.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
81742 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81742 is composite. Its prime factorisation is
- 3
The divisors add up to 128016; without 81742 itself that is 46274, so 81742 is deficient (46274 is less than 81742). Euler's totient φ(81742) = 39072 numbers up to 81742 share no factor with it.
- 4
The digits of 81742 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 213 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81742 = 2 \times 23 \times 1777 \]
81742 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 128016 |
| Euler totient φ(n) | 39072 |
| Square | 6681754564 |
| Cube | 546179981570488 |
| Square root | 285.905579 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 213 |
| Scientific notation | 8.1742 × |
81742 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand seven hundred and forty-two |
| Binary (base 2) | 10011111101001110 |
| Octal (base 8) | 237516 |
| Hexadecimal (base 16) | 13F4E |
| Base 3 | 11011010111 |
| As time | 81742 seconds = 22 h 42 min 22 s |
Is 81742 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81742 ÷ 2 = 40871) | 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 3) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 1) | 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 81742 a prime number?
No. 81742 = 2 × 23 × 1777, so it is divisible by 2.
What are the factors of 81742?
1, 2, 23, 46, 1777, 3554, 40871, 81742.
What is 81742 in binary?
10011111101001110 (hexadecimal 13F4E, octal 237516).
What is the square root of 81742?
About 285.9056.
Is 81742 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 81742?
It is a composite number with 8 divisors.