The number 71731
71731 is a composite number with 4 divisors. Its prime factorisation is 11 × 6521. Divisors (4): 1, 11, 6521, 71731.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 71731: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 11 × 6521, the product of two primes.
- 2
71731 is composite. Its prime factorisation is
- 3
The divisors add up to 78264; without 71731 itself that is 6533, so 71731 is deficient (6533 is less than 71731). Euler's totient φ(71731) = 65200 numbers up to 71731 share no factor with it.
- 4
The digits of 71731 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 231 steps to reach 1.
LaTeX source of the formulas on this page
\[ 71731 = 11 \times 6521 \]
71731 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 78264 |
| Euler totient φ(n) | 65200 |
| Square | 5145336361 |
| Cube | 369080122510891 |
| Square root | 267.826436 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 231 |
| Scientific notation | 7.1731 × |
71731 in other forms
| Form | Value |
|---|---|
| In words | seventy-one thousand seven hundred and thirty-one |
| Binary (base 2) | 10001100000110011 |
| Octal (base 8) | 214063 |
| Hexadecimal (base 16) | 11833 |
| Base 3 | 10122101201 |
| As time | 71731 seconds = 19 h 55 min 31 s |
Is 71731 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 | No (remainder 2) | 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 1) | 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 | Yes (71731 ÷ 11 = 6521) | 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 71731 a prime number?
No. 71731 = 11 × 6521, so it is divisible by 11.
What are the factors of 71731?
1, 11, 6521, 71731.
What is 71731 in binary?
10001100000110011 (hexadecimal 11833, octal 214063).
What is the square root of 71731?
About 267.8264.
Is 71731 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 71731?
71731 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 11 × 6521, the product of two primes.