The number 81942
81942 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 7 × 1951. Divisors (16): 1, 2, 3, 6, 7, 14, 21, 42, 1951, 3902, 5853, 11706, 13657, 27314, 40971, 81942.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
81942 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81942 is composite. Its prime factorisation is
- 3
The divisors add up to 187392; without 81942 itself that is 105450, so 81942 is abundant (105450 is more than 81942). Euler's totient φ(81942) = 23400 numbers up to 81942 share no factor with it.
- 4
The digits of 81942 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 182 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81942 = 2 \times 3 \times 7 \times 1951 \]
81942 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 187392 |
| Euler totient φ(n) | 23400 |
| Square | 6714491364 |
| Cube | 550198851348888 |
| Square root | 286.255131 |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 182 |
| Scientific notation | 8.1942 × |
81942 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand nine hundred and forty-two |
| Binary (base 2) | 10100000000010110 |
| Octal (base 8) | 240026 |
| Hexadecimal (base 16) | 14016 |
| Base 3 | 11011101220 |
| As time | 81942 seconds = 22 h 45 min 42 s |
Is 81942 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81942 ÷ 2 = 40971) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81942 ÷ 3 = 27314) | 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 | Yes (81942 ÷ 6 = 13657) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (81942 ÷ 7 = 11706) | 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 6) | 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 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81942 a prime number?
No. 81942 = 2 × 3 × 7 × 1951, so it is divisible by 2.
What are the factors of 81942?
1, 2, 3, 6, 7, 14, 21, 42, 1951, 3902, 5853, 11706, 13657, 27314, 40971, 81942.
What is 81942 in binary?
10100000000010110 (hexadecimal 14016, octal 240026).
What is the square root of 81942?
About 286.2551.
Is 81942 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 81942?
It is a composite number with 16 divisors.