The number 47820
47820 is a composite number with 24 divisors. Its prime factorisation is × 3 × 5 × 797. Divisors (24): 1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60, 797, 1594, 2391, 3188 … 47820.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 47820: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
47820 is composite. Its prime factorisation is
- 3
The divisors add up to 134064; without 47820 itself that is 86244, so 47820 is abundant (86244 is more than 47820). Euler's totient φ(47820) = 12736 numbers up to 47820 share no factor with it.
- 4
The digits of 47820 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 52 steps to reach 1.
LaTeX source of the formulas on this page
\[ 47820 = 2^{2} \times 3 \times 5 \times 797 \]47820 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 134064 |
| Euler totient φ(n) | 12736 |
| Square | 2286752400 |
| Cube | 109352499768000 |
| Square root | 218.677845 (= 2√11955) |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 52 |
| Scientific notation | 4.782 × |
47820 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand eight hundred and twenty |
| Binary (base 2) | 1011101011001100 |
| Octal (base 8) | 135314 |
| Hexadecimal (base 16) | BACC |
| Base 3 | 2102121010 |
| As time | 47820 seconds = 13 h 17 min 0 s |
Is 47820 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (47820 ÷ 2 = 23910) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (47820 ÷ 3 = 15940) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (47820 ÷ 4 = 11955) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (47820 ÷ 5 = 9564) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (47820 ÷ 6 = 7970) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 3) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (47820 ÷ 10 = 4782) | 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 | Yes (47820 ÷ 12 = 3985) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 47820 a prime number?
No. 47820 = × 3 × 5 × 797, so it is divisible by 2.
What are the factors of 47820?
1, 2, 3, 4, 5, 6, 10, 12, 15, 20, 30, 60, 797, 1594, 2391, 3188, 3985, 4782, 7970, 9564, 11955, 15940, 23910, 47820.
What is 47820 in binary?
1011101011001100 (hexadecimal BACC, octal 135314).
What is the square root of 47820?
About 218.6778, exactly 2√11955.
Is 47820 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 47820?
47820 is a happy number: repeatedly adding the squares of its digits reaches 1.