The number 42870
42870 is a composite number with 16 divisors. Its prime factorisation is 2 × 3 × 5 × 1429. Divisors (16): 1, 2, 3, 5, 6, 10, 15, 30, 1429, 2858, 4287, 7145, 8574, 14290, 21435, 42870.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 42870: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
42870 is composite. Its prime factorisation is
- 3
The divisors add up to 102960; without 42870 itself that is 60090, so 42870 is abundant (60090 is more than 42870). Euler's totient φ(42870) = 11424 numbers up to 42870 share no factor with it.
- 4
The digits of 42870 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 194 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42870 = 2 \times 3 \times 5 \times 1429 \]
42870 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 102960 |
| Euler totient φ(n) | 11424 |
| Square | 1837836900 |
| Cube | 78788067903000 |
| Square root | 207.050718 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 194 |
| Scientific notation | 4.287 × |
42870 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand eight hundred and seventy |
| Binary (base 2) | 1010011101110110 |
| Octal (base 8) | 123566 |
| Hexadecimal (base 16) | A776 |
| Base 3 | 2011210210 |
| As time | 42870 seconds = 11 h 54 min 30 s |
Is 42870 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (42870 ÷ 2 = 21435) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (42870 ÷ 3 = 14290) | 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 (42870 ÷ 5 = 8574) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (42870 ÷ 6 = 7145) | 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 6) | 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 | Yes (42870 ÷ 10 = 4287) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | 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 42870 a prime number?
No. 42870 = 2 × 3 × 5 × 1429, so it is divisible by 2.
What are the factors of 42870?
1, 2, 3, 5, 6, 10, 15, 30, 1429, 2858, 4287, 7145, 8574, 14290, 21435, 42870.
What is 42870 in binary?
1010011101110110 (hexadecimal A776, octal 123566).
What is the square root of 42870?
About 207.0507.
Is 42870 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 42870?
42870 is a happy number: repeatedly adding the squares of its digits reaches 1.