The number 81042
81042 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 13 × 1039. Divisors (16): 1, 2, 3, 6, 13, 26, 39, 78, 1039, 2078, 3117, 6234, 13507, 27014, 40521, 81042.
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How to work it out
- 1
81042 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
81042 is composite. Its prime factorisation is
- 3
The divisors add up to 174720; without 81042 itself that is 93678, so 81042 is abundant (93678 is more than 81042). Euler's totient φ(81042) = 24912 numbers up to 81042 share no factor with it.
- 4
The digits of 81042 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 138 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81042 = 2 \times 3 \times 13 \times 1039 \]
81042 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 174720 |
| Euler totient φ(n) | 24912 |
| Square | 6567805764 |
| Cube | 532268114726088 |
| Square root | 284.678766 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 138 |
| Scientific notation | 8.1042 × |
81042 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand and forty-two |
| Binary (base 2) | 10011110010010010 |
| Octal (base 8) | 236222 |
| Hexadecimal (base 16) | 13C92 |
| Base 3 | 11010011120 |
| As time | 81042 seconds = 22 h 30 min 42 s |
Is 81042 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81042 ÷ 2 = 40521) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81042 ÷ 3 = 27014) | 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 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (81042 ÷ 6 = 13507) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 2) | 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 2) | 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 81042 a prime number?
No. 81042 = 2 × 3 × 13 × 1039, so it is divisible by 2.
What are the factors of 81042?
1, 2, 3, 6, 13, 26, 39, 78, 1039, 2078, 3117, 6234, 13507, 27014, 40521, 81042.
What is 81042 in binary?
10011110010010010 (hexadecimal 13C92, octal 236222).
What is the square root of 81042?
About 284.6788.
Is 81042 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 81042?
It is a composite number with 16 divisors.