The number 21224
21224 is a composite number with 16 divisors. Its prime factorisation is × 7 × 379. Divisors (16): 1, 2, 4, 7, 8, 14, 28, 56, 379, 758, 1516, 2653, 3032, 5306, 10612, 21224.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21224 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21224 is composite. Its prime factorisation is
- 3
The divisors add up to 45600; without 21224 itself that is 24376, so 21224 is abundant (24376 is more than 21224). Euler's totient φ(21224) = 9072 numbers up to 21224 share no factor with it.
- 4
The digits of 21224 add up to 11, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 30 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21224 = 2^{3} \times 7 \times 379 \]21224 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 45600 |
| Euler totient φ(n) | 9072 |
| Square | 450458176 |
| Cube | 9560524327424 |
| Square root | 145.684591 (= 2√5306) |
| Digit sum / digital root | 11 / 2 |
| Collatz steps to 1 | 30 |
| Scientific notation | 2.1224 × |
21224 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand two hundred and twenty-four |
| Binary (base 2) | 101001011101000 |
| Octal (base 8) | 51350 |
| Hexadecimal (base 16) | 52E8 |
| Base 3 | 1002010002 |
| As time | 21224 seconds = 5 h 53 min 44 s |
Is 21224 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21224 ÷ 2 = 10612) | 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 | Yes (21224 ÷ 4 = 5306) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21224 ÷ 7 = 3032) | 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 | Yes (21224 ÷ 8 = 2653) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21224 a prime number?
No. 21224 = × 7 × 379, so it is divisible by 2.
What are the factors of 21224?
1, 2, 4, 7, 8, 14, 28, 56, 379, 758, 1516, 2653, 3032, 5306, 10612, 21224.
What is 21224 in binary?
101001011101000 (hexadecimal 52E8, octal 51350).
What is the square root of 21224?
About 145.6846, exactly 2√5306.
Is 21224 divisible by 3?
No. Its digits add up to 11, which is not a multiple of 3.
What is special about the number 21224?
It is a composite number with 16 divisors.