The number 71085
71085 is a composite number with 16 divisors. Its prime factorisation is 3 × 5 × 7 × 677. Divisors (16): 1, 3, 5, 7, 15, 21, 35, 105, 677, 2031, 3385, 4739, 10155, 14217, 23695, 71085.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 71085: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 21.
- 2
71085 is composite. Its prime factorisation is
- 3
The divisors add up to 130176; without 71085 itself that is 59091, so 71085 is deficient (59091 is less than 71085). Euler's totient φ(71085) = 32448 numbers up to 71085 share no factor with it.
- 4
The digits of 71085 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 73 steps to reach 1.
LaTeX source of the formulas on this page
\[ 71085 = 3 \times 5 \times 7 \times 677 \]
71085 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 130176 |
| Euler totient φ(n) | 32448 |
| Square | 5053077225 |
| Cube | 359197994539125 |
| Square root | 266.617704 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 73 |
| Scientific notation | 7.1085 × |
71085 in other forms
| Form | Value |
|---|---|
| In words | seventy-one thousand and eighty-five |
| Binary (base 2) | 10001010110101101 |
| Octal (base 8) | 212655 |
| Hexadecimal (base 16) | 115AD |
| Base 3 | 10121111210 |
| As time | 71085 seconds = 19 h 44 min 45 s |
Is 71085 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (71085 ÷ 3 = 23695) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (71085 ÷ 5 = 14217) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (71085 ÷ 7 = 10155) | 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 5) | 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 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 71085 a prime number?
No. 71085 = 3 × 5 × 7 × 677, so it is divisible by 3.
What are the factors of 71085?
1, 3, 5, 7, 15, 21, 35, 105, 677, 2031, 3385, 4739, 10155, 14217, 23695, 71085.
What is 71085 in binary?
10001010110101101 (hexadecimal 115AD, octal 212655).
What is the square root of 71085?
About 266.6177.
Is 71085 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 71085?
71085 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 21.