The number 20321
20321 is a composite number with 4 divisors. Its prime factorisation is 7 × 2903. Divisors (4): 1, 7, 2903, 20321.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20321: a semiprime: 7 × 2903, the product of two primes.
- 2
20321 is composite. Its prime factorisation is
- 3
The divisors add up to 23232; without 20321 itself that is 2911, so 20321 is deficient (2911 is less than 20321). Euler's totient φ(20321) = 17412 numbers up to 20321 share no factor with it.
- 4
The digits of 20321 add up to 8, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 180 steps to reach 1.
LaTeX source of the formulas on this page
\[ 20321 = 7 \times 2903 \]
20321 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 23232 |
| Euler totient φ(n) | 17412 |
| Square | 412943041 |
| Cube | 8391415536161 |
| Square root | 142.551745 |
| Digit sum / digital root | 8 / 8 |
| Collatz steps to 1 | 180 |
| Scientific notation | 2.0321 × |
20321 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand three hundred and twenty-one |
| Binary (base 2) | 100111101100001 |
| Octal (base 8) | 47541 |
| Hexadecimal (base 16) | 4F61 |
| Base 3 | 1000212122 |
| As time | 20321 seconds = 5 h 38 min 41 s |
Is 20321 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 | Yes (20321 ÷ 7 = 2903) | 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 8) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20321 a prime number?
No. 20321 = 7 × 2903, so it is divisible by 7.
What are the factors of 20321?
1, 7, 2903, 20321.
What is 20321 in binary?
100111101100001 (hexadecimal 4F61, octal 47541).
What is the square root of 20321?
About 142.5517.
Is 20321 divisible by 3?
No. Its digits add up to 8, which is not a multiple of 3.
What is special about the number 20321?
20321 is a semiprime: 7 × 2903, the product of two primes.