The number 42085
42085 is a composite number with 8 divisors. Its prime factorisation is 5 × 19 × 443. Divisors (8): 1, 5, 19, 95, 443, 2215, 8417, 42085.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42085: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 19.
- 2
42085 is composite. Its prime factorisation is
- 3
The divisors add up to 53280; without 42085 itself that is 11195, so 42085 is deficient (11195 is less than 42085). Euler's totient φ(42085) = 31824 numbers up to 42085 share no factor with it.
- 4
The digits of 42085 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 106 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42085 = 5 \times 19 \times 443 \]
42085 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 53280 |
| Euler totient φ(n) | 31824 |
| Square | 1771147225 |
| Cube | 74538730964125 |
| Square root | 205.146289 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 106 |
| Scientific notation | 4.2085 × |
42085 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand and eighty-five |
| Binary (base 2) | 1010010001100101 |
| Octal (base 8) | 122145 |
| Hexadecimal (base 16) | A465 |
| Base 3 | 2010201201 |
| As time | 42085 seconds = 11 h 41 min 25 s |
Is 42085 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 | No (remainder 1) | 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 (42085 ÷ 5 = 8417) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | 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 5) | 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 | No (remainder 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42085 a prime number?
No. 42085 = 5 × 19 × 443, so it is divisible by 5.
What are the factors of 42085?
1, 5, 19, 95, 443, 2215, 8417, 42085.
What is 42085 in binary?
1010010001100101 (hexadecimal A465, octal 122145).
What is the square root of 42085?
About 205.1463.
Is 42085 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 42085?
42085 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 19.