The number 20221
20221 is a composite number with 4 divisors. Its prime factorisation is 73 × 277. Divisors (4): 1, 73, 277, 20221.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20221: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 73 × 277, the product of two primes.
- 2
20221 is composite. Its prime factorisation is
- 3
The divisors add up to 20572; without 20221 itself that is 351, so 20221 is deficient (351 is less than 20221). Euler's totient φ(20221) = 19872 numbers up to 20221 share no factor with it.
- 4
The digits of 20221 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 87 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20221 = 73 \times 277 \]
20221 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 20572 |
| Euler totient φ(n) | 19872 |
| Square | 408888841 |
| Cube | 8268141253861 |
| Square root | 142.200563 |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 87 |
| Scientific notation | 2.0221 × |
20221 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand two hundred and twenty-one |
| Binary (base 2) | 100111011111101 |
| Octal (base 8) | 47375 |
| Hexadecimal (base 16) | 4EFD |
| Base 3 | 1000201221 |
| As time | 20221 seconds = 5 h 37 min 1 s |
Is 20221 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 5) | 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 7) | 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 3) | 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 20221 a prime number?
No. 20221 = 73 × 277, so it is divisible by 73.
What are the factors of 20221?
1, 73, 277, 20221.
What is 20221 in binary?
100111011111101 (hexadecimal 4EFD, octal 47375).
What is the square root of 20221?
About 142.2006.
Is 20221 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 20221?
20221 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 73 × 277, the product of two primes.