The number 931
931 is a composite number with 6 divisors. Its prime factorisation is Ć 19. Divisors (6): 1, 7, 19, 49, 133, 931.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 931: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
931 is composite. Its prime factorisation is
- 3
The divisors add up to 1140; without 931 itself that is 209, so 931 is deficient (209 is less than 931). Euler's totient Ļ(931) = 756 numbers up to 931 share no factor with it.
- 4
The digits of 931 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 36 steps to reach 1.
LaTeX source of the formulas on this page
\[ 931 = 7^{2} \times 19 \]931 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 1140 |
| Euler totient Ļ(n) | 756 |
| Square | 866761 |
| Cube | 806954491 |
| Square root | 30.512293 (= 7ā19) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 36 |
| Scientific notation | 9.31 Ć |
931 in other forms
| Form | Value |
|---|---|
| In words | nine hundred and thirty-one |
| Roman numerals | CMXXXI |
| Binary (base 2) | 1110100011 |
| Octal (base 8) | 1643 |
| Hexadecimal (base 16) | 3A3 |
| Base 3 | 1021111 |
| As time | 931 seconds = 15 min 31 s |
Is 931 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 1) | 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 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (931 Ć· 7 = 133) | 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 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 931 a prime number?
No. 931 = Ć 19, so it is divisible by 7.
What are the factors of 931?
1, 7, 19, 49, 133, 931.
What is 931 in binary?
1110100011 (hexadecimal 3A3, octal 1643).
What is the square root of 931?
About 30.5123, exactly 7ā19.
What is 931 in Roman numerals?
CMXXXI.
Is 931 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 931?
931 is a happy number: repeatedly adding the squares of its digits reaches 1.