The number 81743
81743 is a composite number with 4 divisors. Its prime factorisation is 43 × 1901. Divisors (4): 1, 43, 1901, 81743.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81743: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 43 × 1901, the product of two primes.
- 2
81743 is composite. Its prime factorisation is
- 3
The divisors add up to 83688; without 81743 itself that is 1945, so 81743 is deficient (1945 is less than 81743). Euler's totient φ(81743) = 79800 numbers up to 81743 share no factor with it.
- 4
The digits of 81743 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 213 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81743 = 43 \times 1901 \]
81743 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 83688 |
| Euler totient φ(n) | 79800 |
| Square | 6681918049 |
| Cube | 546200027079407 |
| Square root | 285.907328 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 213 |
| Scientific notation | 8.1743 × |
81743 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand seven hundred and forty-three |
| Binary (base 2) | 10011111101001111 |
| Octal (base 8) | 237517 |
| Hexadecimal (base 16) | 13F4F |
| Base 3 | 11011010112 |
| As time | 81743 seconds = 22 h 42 min 23 s |
Is 81743 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 3) | 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 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | 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 81743 a prime number?
No. 81743 = 43 × 1901, so it is divisible by 43.
What are the factors of 81743?
1, 43, 1901, 81743.
What is 81743 in binary?
10011111101001111 (hexadecimal 13F4F, octal 237517).
What is the square root of 81743?
About 285.9073.
Is 81743 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 81743?
81743 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 43 × 1901, the product of two primes.