The number 31928
31928 is a composite number with 16 divisors. Its prime factorisation is × 13 × 307. Divisors (16): 1, 2, 4, 8, 13, 26, 52, 104, 307, 614, 1228, 2456, 3991, 7982, 15964, 31928.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
31928 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
31928 is composite. Its prime factorisation is
- 3
The divisors add up to 64680; without 31928 itself that is 32752, so 31928 is abundant (32752 is more than 31928). Euler's totient φ(31928) = 14688 numbers up to 31928 share no factor with it.
- 4
The digits of 31928 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
\[ 31928 = 2^{3} \times 13 \times 307 \]31928 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 64680 |
| Euler totient φ(n) | 14688 |
| Square | 1019397184 |
| Cube | 32547313290752 |
| Square root | 178.684079 (= 2√7982) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 54 |
| Scientific notation | 3.1928 × |
31928 in other forms
| Form | Value |
|---|---|
| In words | thirty-one thousand nine hundred and twenty-eight |
| Binary (base 2) | 111110010111000 |
| Octal (base 8) | 76270 |
| Hexadecimal (base 16) | 7CB8 |
| Base 3 | 1121210112 |
| As time | 31928 seconds = 8 h 52 min 8 s |
Is 31928 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (31928 ÷ 2 = 15964) | 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 | Yes (31928 ÷ 4 = 7982) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | 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 1) | 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 | Yes (31928 ÷ 8 = 3991) | 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 8) | 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 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 31928 a prime number?
No. 31928 = × 13 × 307, so it is divisible by 2.
What are the factors of 31928?
1, 2, 4, 8, 13, 26, 52, 104, 307, 614, 1228, 2456, 3991, 7982, 15964, 31928.
What is 31928 in binary?
111110010111000 (hexadecimal 7CB8, octal 76270).
What is the square root of 31928?
About 178.6841, exactly 2√7982.
Is 31928 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 31928?
It is a composite number with 16 divisors.