The number 21443
21443 is a composite number with 4 divisors. Its prime factorisation is 41 × 523. Divisors (4): 1, 41, 523, 21443.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21443: a semiprime: 41 × 523, the product of two primes.
- 2
21443 is composite. Its prime factorisation is
- 3
The divisors add up to 22008; without 21443 itself that is 565, so 21443 is deficient (565 is less than 21443). Euler's totient φ(21443) = 20880 numbers up to 21443 share no factor with it.
- 4
The digits of 21443 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 100 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21443 = 41 \times 523 \]
21443 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 22008 |
| Euler totient φ(n) | 20880 |
| Square | 459802249 |
| Cube | 9859539625307 |
| Square root | 146.434286 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1443 × |
21443 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and forty-three |
| Binary (base 2) | 101001111000011 |
| Octal (base 8) | 51703 |
| Hexadecimal (base 16) | 53C3 |
| Base 3 | 1002102012 |
| As time | 21443 seconds = 5 h 57 min 23 s |
Is 21443 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | 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 3) | 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 3) | 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 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21443 a prime number?
No. 21443 = 41 × 523, so it is divisible by 41.
What are the factors of 21443?
1, 41, 523, 21443.
What is 21443 in binary?
101001111000011 (hexadecimal 53C3, octal 51703).
What is the square root of 21443?
About 146.4343.
Is 21443 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 21443?
21443 is a semiprime: 41 × 523, the product of two primes.