The number 81313
81313 is a composite number with 8 divisors. Its prime factorisation is 31 × 43 × 61. Divisors (8): 1, 31, 43, 61, 1333, 1891, 2623, 81313.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
81313 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81313 is composite. Its prime factorisation is
- 3
The divisors add up to 87296; without 81313 itself that is 5983, so 81313 is deficient (5983 is less than 81313). Euler's totient φ(81313) = 75600 numbers up to 81313 share no factor with it.
- 4
The digits of 81313 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 182 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81313 = 31 \times 43 \times 61 \]
81313 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 87296 |
| Euler totient φ(n) | 75600 |
| Square | 6611803969 |
| Cube | 537625616131297 |
| Square root | 285.154344 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 182 |
| Scientific notation | 8.1313 × |
81313 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand three hundred and thirteen |
| Binary (base 2) | 10011110110100001 |
| Octal (base 8) | 236641 |
| Hexadecimal (base 16) | 13DA1 |
| Base 3 | 11010112121 |
| As time | 81313 seconds = 22 h 35 min 13 s |
Is 81313 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 1) | 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 1) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | 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 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81313 a prime number?
No. 81313 = 31 × 43 × 61, so it is divisible by 31.
What are the factors of 81313?
1, 31, 43, 61, 1333, 1891, 2623, 81313.
What is 81313 in binary?
10011110110100001 (hexadecimal 13DA1, octal 236641).
What is the square root of 81313?
About 285.1543.
Is 81313 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 81313?
It is a composite number with 8 divisors.