The number 42820
42820 is a composite number with 12 divisors. Its prime factorisation is × 5 × 2141. Divisors (12): 1, 2, 4, 5, 10, 20, 2141, 4282, 8564, 10705, 21410, 42820.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42820 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42820 is composite. Its prime factorisation is
- 3
The divisors add up to 89964; without 42820 itself that is 47144, so 42820 is abundant (47144 is more than 42820). Euler's totient φ(42820) = 17120 numbers up to 42820 share no factor with it.
- 4
The digits of 42820 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 49 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42820 = 2^{2} \times 5 \times 2141 \]42820 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 89964 |
| Euler totient φ(n) | 17120 |
| Square | 1833552400 |
| Cube | 78512713768000 |
| Square root | 206.929940 (= 2√10705) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 49 |
| Scientific notation | 4.282 × |
42820 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand eight hundred and twenty |
| Binary (base 2) | 1010011101000100 |
| Octal (base 8) | 123504 |
| Hexadecimal (base 16) | A744 |
| Base 3 | 2011201221 |
| As time | 42820 seconds = 11 h 53 min 40 s |
Is 42820 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42820 ÷ 2 = 21410) | 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 | Yes (42820 ÷ 4 = 10705) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (42820 ÷ 5 = 8564) | 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 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (42820 ÷ 10 = 4282) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42820 a prime number?
No. 42820 = × 5 × 2141, so it is divisible by 2.
What are the factors of 42820?
1, 2, 4, 5, 10, 20, 2141, 4282, 8564, 10705, 21410, 42820.
What is 42820 in binary?
1010011101000100 (hexadecimal A744, octal 123504).
What is the square root of 42820?
About 206.9299, exactly 2√10705.
Is 42820 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 42820?
It is a composite number with 12 divisors.