The number 42390
42390 is a composite number with 32 divisors. Its prime factorisation is 2 × × 5 × 157. Divisors (32): 1, 2, 3, 5, 6, 9, 10, 15, 18, 27, 30, 45, 54, 90, 135, 157 … 42390.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42390: a Harshad number: divisible by its digit sum 18.
- 2
42390 is composite. Its prime factorisation is
- 3
The divisors add up to 113760; without 42390 itself that is 71370, so 42390 is abundant (71370 is more than 42390). Euler's totient φ(42390) = 11232 numbers up to 42390 share no factor with it.
- 4
The digits of 42390 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 57 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42390 = 2 \times 3^{3} \times 5 \times 157 \]42390 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 32 |
| Sum of divisors | 113760 |
| Euler totient φ(n) | 11232 |
| Square | 1796912100 |
| Cube | 76171103919000 |
| Square root | 205.888319 (= 3√4710) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 57 |
| Scientific notation | 4.239 × |
42390 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand three hundred and ninety |
| Binary (base 2) | 1010010110010110 |
| Octal (base 8) | 122626 |
| Hexadecimal (base 16) | A596 |
| Base 3 | 2011011000 |
| As time | 42390 seconds = 11 h 46 min 30 s |
Is 42390 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42390 ÷ 2 = 21195) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (42390 ÷ 3 = 14130) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (42390 ÷ 5 = 8478) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (42390 ÷ 6 = 7065) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (42390 ÷ 9 = 4710) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (42390 ÷ 10 = 4239) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42390 a prime number?
No. 42390 = 2 × × 5 × 157, so it is divisible by 2.
What are the factors of 42390?
1, 2, 3, 5, 6, 9, 10, 15, 18, 27, 30, 45, 54, 90, 135, 157, 270, 314, 471, 785, 942, 1413, 1570, 2355, 2826, 4239, 4710, 7065, 8478, 14130, 21195, 42390.
What is 42390 in binary?
1010010110010110 (hexadecimal A596, octal 122626).
What is the square root of 42390?
About 205.8883, exactly 3√4710.
Is 42390 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 42390?
42390 is a Harshad number: divisible by its digit sum 18.