The number 47921
47921 is a composite number with 4 divisors. Its prime factorisation is 173 × 277. Divisors (4): 1, 173, 277, 47921.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 47921: a semiprime: 173 × 277, the product of two primes.
- 2
47921 is composite. Its prime factorisation is
- 3
The divisors add up to 48372; without 47921 itself that is 451, so 47921 is deficient (451 is less than 47921). Euler's totient φ(47921) = 47472 numbers up to 47921 share no factor with it.
- 4
The digits of 47921 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 189 steps to reach 1.
LaTeX source of the formulas on this page
\[ 47921 = 173 \times 277 \]
47921 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 48372 |
| Euler totient φ(n) | 47472 |
| Square | 2296422241 |
| Cube | 110046850210961 |
| Square root | 218.908657 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 189 |
| Scientific notation | 4.7921 × |
47921 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand nine hundred and twenty-one |
| Binary (base 2) | 1011101100110001 |
| Octal (base 8) | 135461 |
| Hexadecimal (base 16) | BB31 |
| Base 3 | 2102201212 |
| As time | 47921 seconds = 13 h 18 min 41 s |
Is 47921 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 2) | 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 1) | 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 | No (remainder 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 47921 a prime number?
No. 47921 = 173 × 277, so it is divisible by 173.
What are the factors of 47921?
1, 173, 277, 47921.
What is 47921 in binary?
1011101100110001 (hexadecimal BB31, octal 135461).
What is the square root of 47921?
About 218.9087.
Is 47921 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 47921?
47921 is a semiprime: 173 × 277, the product of two primes.