The number 31982
31982 is a composite number with 4 divisors. Its prime factorisation is 2 × 15991. Divisors (4): 1, 2, 15991, 31982.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31982: a semiprime: 2 × 15991, the product of two primes.
- 2
31982 is composite. Its prime factorisation is
- 3
The divisors add up to 47976; without 31982 itself that is 15994, so 31982 is deficient (15994 is less than 31982). Euler's totient φ(31982) = 15990 numbers up to 31982 share no factor with it.
- 4
The digits of 31982 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 54 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31982 = 2 \times 15991 \]
31982 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 47976 |
| Euler totient φ(n) | 15990 |
| Square | 1022848324 |
| Cube | 32712735098168 |
| Square root | 178.835120 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 54 |
| Scientific notation | 3.1982 × |
31982 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and eighty-two |
| Binary (base 2) | 111110011101110 |
| Octal (base 8) | 76356 |
| Hexadecimal (base 16) | 7CEE |
| Base 3 | 1121212112 |
| As time | 31982 seconds = 8 h 53 min 2 s |
Is 31982 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31982 ÷ 2 = 15991) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | 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 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 5) | 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 2) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31982 a prime number?
No. 31982 = 2 × 15991, so it is divisible by 2.
What are the factors of 31982?
1, 2, 15991, 31982.
What is 31982 in binary?
111110011101110 (hexadecimal 7CEE, octal 76356).
What is the square root of 31982?
About 178.8351.
Is 31982 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 31982?
31982 is a semiprime: 2 × 15991, the product of two primes.