The number 31979
31979 is a composite number with 4 divisors. Its prime factorisation is 113 × 283. Divisors (4): 1, 113, 283, 31979.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31979: a semiprime: 113 × 283, the product of two primes.
- 2
31979 is composite. Its prime factorisation is
- 3
The divisors add up to 32376; without 31979 itself that is 397, so 31979 is deficient (397 is less than 31979). Euler's totient φ(31979) = 31584 numbers up to 31979 share no factor with it.
- 4
The digits of 31979 add up to 29, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 98 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31979 = 113 \times 283 \]
31979 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 32376 |
| Euler totient φ(n) | 31584 |
| Square | 1022656441 |
| Cube | 32703530326739 |
| Square root | 178.826732 |
| Digit sum / digital root | 29 / 2 |
| Collatz steps to 1 | 98 |
| Scientific notation | 3.1979 × |
31979 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and seventy-nine |
| Binary (base 2) | 111110011101011 |
| Octal (base 8) | 76353 |
| Hexadecimal (base 16) | 7CEB |
| Base 3 | 1121212102 |
| As time | 31979 seconds = 8 h 52 min 59 s |
Is 31979 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31979 a prime number?
No. 31979 = 113 × 283, so it is divisible by 113.
What are the factors of 31979?
1, 113, 283, 31979.
What is 31979 in binary?
111110011101011 (hexadecimal 7CEB, octal 76353).
What is the square root of 31979?
About 178.8267.
Is 31979 divisible by 3?
No. Its digits add up to 29, which is not a multiple of 3.
What is special about the number 31979?
31979 is a semiprime: 113 × 283, the product of two primes.