The number 81142
81142 is a composite number with 8 divisors. Its prime factorisation is 2 × 29 × 1399. Divisors (8): 1, 2, 29, 58, 1399, 2798, 40571, 81142.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81142: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
81142 is composite. Its prime factorisation is
- 3
The divisors add up to 126000; without 81142 itself that is 44858, so 81142 is deficient (44858 is less than 81142). Euler's totient φ(81142) = 39144 numbers up to 81142 share no factor with it.
- 4
The digits of 81142 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 89 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81142 = 2 \times 29 \times 1399 \]
81142 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 126000 |
| Euler totient φ(n) | 39144 |
| Square | 6584024164 |
| Cube | 534240888715288 |
| Square root | 284.854349 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 89 |
| Scientific notation | 8.1142 × |
81142 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand one hundred and forty-two |
| Binary (base 2) | 10011110011110110 |
| Octal (base 8) | 236366 |
| Hexadecimal (base 16) | 13CF6 |
| Base 3 | 11010022021 |
| As time | 81142 seconds = 22 h 32 min 22 s |
Is 81142 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81142 ÷ 2 = 40571) | 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 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | 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 6) | 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 81142 a prime number?
No. 81142 = 2 × 29 × 1399, so it is divisible by 2.
What are the factors of 81142?
1, 2, 29, 58, 1399, 2798, 40571, 81142.
What is 81142 in binary?
10011110011110110 (hexadecimal 13CF6, octal 236366).
What is the square root of 81142?
About 284.8543.
Is 81142 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 81142?
81142 is a happy number: repeatedly adding the squares of its digits reaches 1.