The number 21223
21223 is a composite number with 4 divisors. Its prime factorisation is 19 × 1117. Divisors (4): 1, 19, 1117, 21223.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21223: a semiprime: 19 × 1117, the product of two primes.
- 2
21223 is composite. Its prime factorisation is
- 3
The divisors add up to 22360; without 21223 itself that is 1137, so 21223 is deficient (1137 is less than 21223). Euler's totient φ(21223) = 20088 numbers up to 21223 share no factor with it.
- 4
The digits of 21223 add up to 10, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 149 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21223 = 19 \times 1117 \]
21223 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 22360 |
| Euler totient φ(n) | 20088 |
| Square | 450415729 |
| Cube | 9559173016567 |
| Square root | 145.681159 |
| Digit sum / digital root | 10 / 1 |
| Collatz steps to 1 | 149 |
| Scientific notation | 2.1223 × |
21223 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand two hundred and twenty-three |
| Binary (base 2) | 101001011100111 |
| Octal (base 8) | 51347 |
| Hexadecimal (base 16) | 52E7 |
| Base 3 | 1002010001 |
| As time | 21223 seconds = 5 h 53 min 43 s |
Is 21223 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 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 1) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | 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 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21223 a prime number?
No. 21223 = 19 × 1117, so it is divisible by 19.
What are the factors of 21223?
1, 19, 1117, 21223.
What is 21223 in binary?
101001011100111 (hexadecimal 52E7, octal 51347).
What is the square root of 21223?
About 145.6812.
Is 21223 divisible by 3?
No. Its digits add up to 10, which is not a multiple of 3.
What is special about the number 21223?
21223 is a semiprime: 19 × 1117, the product of two primes.