The number 82
82 is a composite number with 4 divisors. Its prime factorisation is 2 × 41. Divisors (4): 1, 2, 41, 82.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 82: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 2 × 41, the product of two primes.
- 2
82 is composite. Its prime factorisation is
- 3
The divisors add up to 126; without 82 itself that is 44, so 82 is deficient (44 is less than 82). Euler's totient φ(82) = 40 numbers up to 82 share no factor with it.
- 4
The digits of 82 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 110 steps to reach 1.
LaTeX source of the formulas on this page
\[ 82 = 2 \times 41 \]
82 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 126 |
| Euler totient φ(n) | 40 |
| Square | 6724 |
| Cube | 551368 |
| Square root | 9.055385 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 110 |
| Scientific notation | 8.2 × |
82 in other forms
| Form | Value |
|---|---|
| In words | eighty-two |
| Roman numerals | LXXXII |
| Binary (base 2) | 1010010 |
| Octal (base 8) | 122 |
| Hexadecimal (base 16) | 52 |
| Base 3 | 10001 |
| As time | 82 seconds = 1 min 22 s |
Is 82 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (82 ÷ 2 = 41) | 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 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 5) | 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 82 a prime number?
No. 82 = 2 × 41, so it is divisible by 2.
What are the factors of 82?
1, 2, 41, 82.
What is 82 in binary?
1010010 (hexadecimal 52, octal 122).
What is the square root of 82?
About 9.0554.
What is 82 in Roman numerals?
LXXXII.
Is 82 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 82?
82 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 2 × 41, the product of two primes.