The number 81010
81010 is a composite number with 8 divisors. Its prime factorisation is 2 × 5 × 8101. Divisors (8): 1, 2, 5, 10, 8101, 16202, 40505, 81010.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 81010: a Harshad number: divisible by its digit sum 10.
- 2
81010 is composite. Its prime factorisation is
- 3
The divisors add up to 145836; without 81010 itself that is 64826, so 81010 is deficient (64826 is less than 81010). Euler's totient φ(81010) = 32400 numbers up to 81010 share no factor with it.
- 4
The digits of 81010 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 89 steps to reach 1.
LaTeX source of the formulas on this page
\[ 81010 = 2 \times 5 \times 8101 \]
81010 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 145836 |
| Euler totient φ(n) | 32400 |
| Square | 6562620100 |
| Cube | 531637854301000 |
| Square root | 284.622557 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 89 |
| Scientific notation | 8.101 × |
81010 in other forms
| Form | Value |
|---|---|
| In words | eighty-one thousand and ten |
| Binary (base 2) | 10011110001110010 |
| Octal (base 8) | 236162 |
| Hexadecimal (base 16) | 13C72 |
| Base 3 | 11010010101 |
| As time | 81010 seconds = 22 h 30 min 10 s |
Is 81010 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (81010 ÷ 2 = 40505) | 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 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (81010 ÷ 5 = 16202) | 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 | No (remainder 2) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (81010 ÷ 10 = 8101) | 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 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 81010 a prime number?
No. 81010 = 2 × 5 × 8101, so it is divisible by 2.
What are the factors of 81010?
1, 2, 5, 10, 8101, 16202, 40505, 81010.
What is 81010 in binary?
10011110001110010 (hexadecimal 13C72, octal 236162).
What is the square root of 81010?
About 284.6226.
Is 81010 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 81010?
81010 is a Harshad number: divisible by its digit sum 10.