The number 30731
30731 is a composite number with 4 divisors. Its prime factorisation is 79 × 389. Divisors (4): 1, 79, 389, 30731.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 30731: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 79 × 389, the product of two primes.
- 2
30731 is composite. Its prime factorisation is
- 3
The divisors add up to 31200; without 30731 itself that is 469, so 30731 is deficient (469 is less than 30731). Euler's totient φ(30731) = 30264 numbers up to 30731 share no factor with it.
- 4
The digits of 30731 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 178 steps to reach 1.
LaTeX source of the formulas on this page
\[ 30731 = 79 \times 389 \]
30731 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 31200 |
| Euler totient φ(n) | 30264 |
| Square | 944394361 |
| Cube | 29022183107891 |
| Square root | 175.302596 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 178 |
| Scientific notation | 3.0731 × |
30731 in other forms
| Form | Value |
|---|---|
| In words | thirty thousand seven hundred and thirty-one |
| Binary (base 2) | 111100000001011 |
| Octal (base 8) | 74013 |
| Hexadecimal (base 16) | 780B |
| Base 3 | 1120011012 |
| As time | 30731 seconds = 8 h 32 min 11 s |
Is 30731 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 1) | 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 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 | No (remainder 3) | 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 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | 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 30731 a prime number?
No. 30731 = 79 × 389, so it is divisible by 79.
What are the factors of 30731?
1, 79, 389, 30731.
What is 30731 in binary?
111100000001011 (hexadecimal 780B, octal 74013).
What is the square root of 30731?
About 175.3026.
Is 30731 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 30731?
30731 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 79 × 389, the product of two primes.