The number 81012
81012 is a composite number with 24 divisors. Its prime factorisation is × 3 × 43 × 157. Divisors (24): 1, 2, 3, 4, 6, 12, 43, 86, 129, 157, 172, 258, 314, 471, 516, 628 … 81012.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81012: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 12.
- 2
81012 is composite. Its prime factorisation is
- 3
The divisors add up to 194656; without 81012 itself that is 113644, so 81012 is abundant (113644 is more than 81012). Euler's totient φ(81012) = 26208 numbers up to 81012 share no factor with it.
- 4
The digits of 81012 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 138 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81012 = 2^{2} \times 3 \times 43 \times 157 \]81012 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 194656 |
| Euler totient φ(n) | 26208 |
| Square | 6562944144 |
| Cube | 531677230993728 |
| Square root | 284.626070 (= 2√20253) |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 138 |
| Scientific notation | 8.1012 × |
81012 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand and twelve |
| Binary (base 2) | 10011110001110100 |
| Octal (base 8) | 236164 |
| Hexadecimal (base 16) | 13C74 |
| Base 3 | 11010010110 |
| As time | 81012 seconds = 22 h 30 min 12 s |
Is 81012 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81012 ÷ 2 = 40506) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (81012 ÷ 3 = 27004) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (81012 ÷ 4 = 20253) | 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 (81012 ÷ 6 = 13502) | 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 4) | 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 2) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (81012 ÷ 12 = 6751) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81012 a prime number?
No. 81012 = × 3 × 43 × 157, so it is divisible by 2.
What are the factors of 81012?
1, 2, 3, 4, 6, 12, 43, 86, 129, 157, 172, 258, 314, 471, 516, 628, 942, 1884, 6751, 13502, 20253, 27004, 40506, 81012.
What is 81012 in binary?
10011110001110100 (hexadecimal 13C74, octal 236164).
What is the square root of 81012?
About 284.6261, exactly 2√20253.
Is 81012 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 81012?
81012 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 12.