The number 81472
81472 is a composite number with 28 divisors. Its prime factorisation is × 19 × 67. Divisors (28): 1, 2, 4, 8, 16, 19, 32, 38, 64, 67, 76, 134, 152, 268, 304, 536 … 81472.
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How to work it out
- 1
81472 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81472 is composite. Its prime factorisation is
- 3
The divisors add up to 172720; without 81472 itself that is 91248, so 81472 is abundant (91248 is more than 81472). Euler's totient φ(81472) = 38016 numbers up to 81472 share no factor with it.
- 4
The digits of 81472 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 37 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81472 = 2^{6} \times 19 \times 67 \]81472 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 28 |
| Sum of divisors | 172720 |
| Euler totient φ(n) | 38016 |
| Square | 6637686784 |
| Cube | 540785617666048 |
| Square root | 285.433004 (= 8√1273) |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 37 |
| Scientific notation | 8.1472 × |
81472 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand four hundred and seventy-two |
| Binary (base 2) | 10011111001000000 |
| Octal (base 8) | 237100 |
| Hexadecimal (base 16) | 13E40 |
| Base 3 | 11010202111 |
| As time | 81472 seconds = 22 h 37 min 52 s |
Is 81472 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81472 ÷ 2 = 40736) | 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 | Yes (81472 ÷ 4 = 20368) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 (81472 ÷ 8 = 10184) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81472 a prime number?
No. 81472 = × 19 × 67, so it is divisible by 2.
What are the factors of 81472?
1, 2, 4, 8, 16, 19, 32, 38, 64, 67, 76, 134, 152, 268, 304, 536, 608, 1072, 1216, 1273, 2144, 2546, 4288, 5092, 10184, 20368, 40736, 81472.
What is 81472 in binary?
10011111001000000 (hexadecimal 13E40, octal 237100).
What is the square root of 81472?
About 285.4330, exactly 8√1273.
Is 81472 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 81472?
It is a composite number with 28 divisors.