The number 47821
47821 is a composite number with 8 divisors. Its prime factorisation is 17 × 29 × 97. Divisors (8): 1, 17, 29, 97, 493, 1649, 2813, 47821.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
47821 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
47821 is composite. Its prime factorisation is
- 3
The divisors add up to 52920; without 47821 itself that is 5099, so 47821 is deficient (5099 is less than 47821). Euler's totient φ(47821) = 43008 numbers up to 47821 share no factor with it.
- 4
The digits of 47821 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 52 steps to reach 1.
LaTeX source of the formulas on this page
\[ 47821 = 17 \times 29 \times 97 \]
47821 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 52920 |
| Euler totient φ(n) | 43008 |
| Square | 2286848041 |
| Cube | 109359360168661 |
| Square root | 218.680132 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 52 |
| Scientific notation | 4.7821 × |
47821 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand eight hundred and twenty-one |
| Binary (base 2) | 1011101011001101 |
| Octal (base 8) | 135315 |
| Hexadecimal (base 16) | BACD |
| Base 3 | 2102121011 |
| As time | 47821 seconds = 13 h 17 min 1 s |
Is 47821 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 47821 a prime number?
No. 47821 = 17 × 29 × 97, so it is divisible by 17.
What are the factors of 47821?
1, 17, 29, 97, 493, 1649, 2813, 47821.
What is 47821 in binary?
1011101011001101 (hexadecimal BACD, octal 135315).
What is the square root of 47821?
About 218.6801.
Is 47821 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 47821?
It is a composite number with 8 divisors.