The number 42205
42205 is a composite number with 8 divisors. Its prime factorisation is 5 × 23 × 367. Divisors (8): 1, 5, 23, 115, 367, 1835, 8441, 42205.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42205: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
42205 is composite. Its prime factorisation is
- 3
The divisors add up to 52992; without 42205 itself that is 10787, so 42205 is deficient (10787 is less than 42205). Euler's totient φ(42205) = 32208 numbers up to 42205 share no factor with it.
- 4
The digits of 42205 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 106 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42205 = 5 \times 23 \times 367 \]
42205 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 52992 |
| Euler totient φ(n) | 32208 |
| Square | 1781262025 |
| Cube | 75178163765125 |
| Square root | 205.438555 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 106 |
| Scientific notation | 4.2205 × |
42205 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand two hundred and five |
| Binary (base 2) | 1010010011011101 |
| Octal (base 8) | 122335 |
| Hexadecimal (base 16) | A4DD |
| Base 3 | 2010220011 |
| As time | 42205 seconds = 11 h 43 min 25 s |
Is 42205 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 (42205 ÷ 5 = 8441) | 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 2) | 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 4) | 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 9) | 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 42205 a prime number?
No. 42205 = 5 × 23 × 367, so it is divisible by 5.
What are the factors of 42205?
1, 5, 23, 115, 367, 1835, 8441, 42205.
What is 42205 in binary?
1010010011011101 (hexadecimal A4DD, octal 122335).
What is the square root of 42205?
About 205.4386.
Is 42205 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 42205?
42205 is a happy number: repeatedly adding the squares of its digits reaches 1.