The number 42645
42645 is a composite number with 8 divisors. Its prime factorisation is 3 × 5 × 2843. Divisors (8): 1, 3, 5, 15, 2843, 8529, 14215, 42645.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42645: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
42645 is composite. Its prime factorisation is
- 3
The divisors add up to 68256; without 42645 itself that is 25611, so 42645 is deficient (25611 is less than 42645). Euler's totient φ(42645) = 22736 numbers up to 42645 share no factor with it.
- 4
The digits of 42645 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 57 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42645 = 3 \times 5 \times 2843 \]
42645 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 68256 |
| Euler totient φ(n) | 22736 |
| Square | 1818596025 |
| Cube | 77554027486125 |
| Square root | 206.506658 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 57 |
| Scientific notation | 4.2645 × |
42645 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand six hundred and forty-five |
| Binary (base 2) | 1010011010010101 |
| Octal (base 8) | 123225 |
| Hexadecimal (base 16) | A695 |
| Base 3 | 2011111110 |
| As time | 42645 seconds = 11 h 50 min 45 s |
Is 42645 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 (42645 ÷ 3 = 14215) | 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 (42645 ÷ 5 = 8529) | 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 | 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 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 9) | 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 42645 a prime number?
No. 42645 = 3 × 5 × 2843, so it is divisible by 3.
What are the factors of 42645?
1, 3, 5, 15, 2843, 8529, 14215, 42645.
What is 42645 in binary?
1010011010010101 (hexadecimal A695, octal 123225).
What is the square root of 42645?
About 206.5067.
Is 42645 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 42645?
42645 is a happy number: repeatedly adding the squares of its digits reaches 1.