The number 81264
81264 is a composite number with 20 divisors. Its prime factorisation is × 3 × 1693. Divisors (20): 1, 2, 3, 4, 6, 8, 12, 16, 24, 48, 1693, 3386, 5079, 6772, 10158, 13544 … 81264.
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How to work it out
- 1
81264 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81264 is composite. Its prime factorisation is
- 3
The divisors add up to 210056; without 81264 itself that is 128792, so 81264 is abundant (128792 is more than 81264). Euler's totient φ(81264) = 27072 numbers up to 81264 share no factor with it.
- 4
The digits of 81264 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 182 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81264 = 2^{4} \times 3 \times 1693 \]81264 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 210056 |
| Euler totient φ(n) | 27072 |
| Square | 6603837696 |
| Cube | 536654266527744 |
| Square root | 285.068413 (= 4√5079) |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 182 |
| Scientific notation | 8.1264 × |
81264 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand two hundred and sixty-four |
| Binary (base 2) | 10011110101110000 |
| Octal (base 8) | 236560 |
| Hexadecimal (base 16) | 13D70 |
| Base 3 | 11010110210 |
| As time | 81264 seconds = 22 h 34 min 24 s |
Is 81264 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81264 ÷ 2 = 40632) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81264 ÷ 3 = 27088) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (81264 ÷ 4 = 20316) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (81264 ÷ 6 = 13544) | 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 | Yes (81264 ÷ 8 = 10158) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 4) | 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 | Yes (81264 ÷ 12 = 6772) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81264 a prime number?
No. 81264 = × 3 × 1693, so it is divisible by 2.
What are the factors of 81264?
1, 2, 3, 4, 6, 8, 12, 16, 24, 48, 1693, 3386, 5079, 6772, 10158, 13544, 20316, 27088, 40632, 81264.
What is 81264 in binary?
10011110101110000 (hexadecimal 13D70, octal 236560).
What is the square root of 81264?
About 285.0684, exactly 4√5079.
Is 81264 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 81264?
It is a composite number with 20 divisors.