The number 47840
47840 is a composite number with 48 divisors. Its prime factorisation is × 5 × 13 × 23. Divisors (48): 1, 2, 4, 5, 8, 10, 13, 16, 20, 23, 26, 32, 40, 46, 52, 65 … 47840.
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How to work it out
- 1
What is special about 47840: a Harshad number: divisible by its digit sum 23.
- 2
47840 is composite. Its prime factorisation is
- 3
The divisors add up to 127008; without 47840 itself that is 79168, so 47840 is abundant (79168 is more than 47840). Euler's totient φ(47840) = 16896 numbers up to 47840 share no factor with it.
- 4
The digits of 47840 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 52 steps to reach 1.
LaTeX source of the formulas on this page
\[ 47840 = 2^{5} \times 5 \times 13 \times 23 \]47840 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 48 |
| Sum of divisors | 127008 |
| Euler totient φ(n) | 16896 |
| Square | 2288665600 |
| Cube | 109489762304000 |
| Square root | 218.723570 (= 4√2990) |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 52 |
| Scientific notation | 4.784 × |
47840 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand eight hundred and forty |
| Binary (base 2) | 1011101011100000 |
| Octal (base 8) | 135340 |
| Hexadecimal (base 16) | BAE0 |
| Base 3 | 2102121212 |
| As time | 47840 seconds = 13 h 17 min 20 s |
Is 47840 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (47840 ÷ 2 = 23920) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (47840 ÷ 4 = 11960) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (47840 ÷ 5 = 9568) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | 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 | Yes (47840 ÷ 8 = 5980) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (47840 ÷ 10 = 4784) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 47840 a prime number?
No. 47840 = × 5 × 13 × 23, so it is divisible by 2.
What are the factors of 47840?
1, 2, 4, 5, 8, 10, 13, 16, 20, 23, 26, 32, 40, 46, 52, 65, 80, 92, 104, 115, 130, 160, 184, 208, 230, 260, 299, 368, 416, 460, 520, 598, 736, 920, 1040, 1196, 1495, 1840, 2080, 2392, 2990, 3680, 4784, 5980, 9568, 11960, 23920, 47840.
What is 47840 in binary?
1011101011100000 (hexadecimal BAE0, octal 135340).
What is the square root of 47840?
About 218.7236, exactly 4√2990.
Is 47840 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 47840?
47840 is a Harshad number: divisible by its digit sum 23.