The number 31679
31679 is a composite number with 4 divisors. Its prime factorisation is 79 × 401. Divisors (4): 1, 79, 401, 31679.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 31679: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 79 × 401, the product of two primes.
- 2
31679 is composite. Its prime factorisation is
- 3
The divisors add up to 32160; without 31679 itself that is 481, so 31679 is deficient (481 is less than 31679). Euler's totient φ(31679) = 31200 numbers up to 31679 share no factor with it.
- 4
The digits of 31679 add up to 26, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 77 steps to reach 1.
LaTeX source of the formulas on this page
\[ 31679 = 79 \times 401 \]
31679 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 32160 |
| Euler totient φ(n) | 31200 |
| Square | 1003559041 |
| Cube | 31791746859839 |
| Square root | 177.985955 |
| Digit sum / digital root | 26 / 8 |
| Collatz steps to 1 | 77 |
| Scientific notation | 3.1679 × |
31679 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand six hundred and seventy-nine |
| Binary (base 2) | 111101110111111 |
| Octal (base 8) | 75677 |
| Hexadecimal (base 16) | 7BBF |
| Base 3 | 1121110022 |
| As time | 31679 seconds = 8 h 47 min 59 s |
Is 31679 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 4) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | 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 10) | 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 31679 a prime number?
No. 31679 = 79 × 401, so it is divisible by 79.
What are the factors of 31679?
1, 79, 401, 31679.
What is 31679 in binary?
111101110111111 (hexadecimal 7BBF, octal 75677).
What is the square root of 31679?
About 177.9860.
Is 31679 divisible by 3?
No. Its digits add up to 26, which is not a multiple of 3.
What is special about the number 31679?
31679 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 79 × 401, the product of two primes.