The number 81438
81438 is a composite number with 24 divisors. Its prime factorisation is 2 × 3 × × 277. Divisors (24): 1, 2, 3, 6, 7, 14, 21, 42, 49, 98, 147, 277, 294, 554, 831, 1662 … 81438.
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How to work it out
- 1
81438 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81438 is composite. Its prime factorisation is
- 3
The divisors add up to 190152; without 81438 itself that is 108714, so 81438 is abundant (108714 is more than 81438). Euler's totient φ(81438) = 23184 numbers up to 81438 share no factor with it.
- 4
The digits of 81438 add up to 24, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 37 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81438 = 2 \times 3 \times 7^{2} \times 277 \]81438 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 190152 |
| Euler totient φ(n) | 23184 |
| Square | 6632147844 |
| Cube | 540108856119672 |
| Square root | 285.373440 (= 7√1662) |
| Digit sum / digital root | 24 / 6 |
| Collatz steps to 1 | 37 |
| Scientific notation | 8.1438 × |
81438 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand four hundred and thirty-eight |
| Binary (base 2) | 10011111000011110 |
| Octal (base 8) | 237036 |
| Hexadecimal (base 16) | 13E1E |
| Base 3 | 11010201020 |
| As time | 81438 seconds = 22 h 37 min 18 s |
Is 81438 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81438 ÷ 2 = 40719) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81438 ÷ 3 = 27146) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | 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 | Yes (81438 ÷ 6 = 13573) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (81438 ÷ 7 = 11634) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81438 a prime number?
No. 81438 = 2 × 3 × × 277, so it is divisible by 2.
What are the factors of 81438?
1, 2, 3, 6, 7, 14, 21, 42, 49, 98, 147, 277, 294, 554, 831, 1662, 1939, 3878, 5817, 11634, 13573, 27146, 40719, 81438.
What is 81438 in binary?
10011111000011110 (hexadecimal 13E1E, octal 237036).
What is the square root of 81438?
About 285.3734, exactly 7√1662.
Is 81438 divisible by 3?
Yes. Its digits add up to 24, a multiple of 3.
What is special about the number 81438?
It is a composite number with 24 divisors.