The number 47021
47021 is a composite number with 4 divisors. Its prime factorisation is 13 × 3617. Divisors (4): 1, 13, 3617, 47021.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 47021: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 13 × 3617, the product of two primes.
- 2
47021 is composite. Its prime factorisation is
- 3
The divisors add up to 50652; without 47021 itself that is 3631, so 47021 is deficient (3631 is less than 47021). Euler's totient φ(47021) = 43392 numbers up to 47021 share no factor with it.
- 4
The digits of 47021 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 158 steps to reach 1.
LaTeX source of the formulas on this page
\[ 47021 = 13 \times 3617 \]
47021 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 50652 |
| Euler totient φ(n) | 43392 |
| Square | 2210974441 |
| Cube | 103962229190261 |
| Square root | 216.843261 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 158 |
| Scientific notation | 4.7021 × |
47021 in other forms
| Form | Value |
|---|---|
| In words | forty-seven thousand and twenty-one |
| Binary (base 2) | 1011011110101101 |
| Octal (base 8) | 133655 |
| Hexadecimal (base 16) | B7AD |
| Base 3 | 2101111112 |
| As time | 47021 seconds = 13 h 3 min 41 s |
Is 47021 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 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 5) | 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 7) | 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 47021 a prime number?
No. 47021 = 13 × 3617, so it is divisible by 13.
What are the factors of 47021?
1, 13, 3617, 47021.
What is 47021 in binary?
1011011110101101 (hexadecimal B7AD, octal 133655).
What is the square root of 47021?
About 216.8433.
Is 47021 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 47021?
47021 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 13 × 3617, the product of two primes.