The number 21222
21222 is a composite number with 20 divisors. Its prime factorisation is 2 × × 131. Divisors (20): 1, 2, 3, 6, 9, 18, 27, 54, 81, 131, 162, 262, 393, 786, 1179, 2358 … 21222.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21222: a Harshad number: divisible by its digit sum 9.
- 2
21222 is composite. Its prime factorisation is
- 3
The divisors add up to 47916; without 21222 itself that is 26694, so 21222 is abundant (26694 is more than 21222). Euler's totient φ(21222) = 7020 numbers up to 21222 share no factor with it.
- 4
The digits of 21222 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 100 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21222 = 2 \times 3^{4} \times 131 \]21222 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 47916 |
| Euler totient φ(n) | 7020 |
| Square | 450373284 |
| Cube | 9557821833048 |
| Square root | 145.677727 (= 9√262) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1222 × |
21222 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand two hundred and twenty-two |
| Binary (base 2) | 101001011100110 |
| Octal (base 8) | 51346 |
| Hexadecimal (base 16) | 52E6 |
| Base 3 | 1002010000 |
| As time | 21222 seconds = 5 h 53 min 42 s |
Is 21222 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21222 ÷ 2 = 10611) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21222 ÷ 3 = 7074) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (21222 ÷ 6 = 3537) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (21222 ÷ 9 = 2358) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 2) | 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 6) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21222 a prime number?
No. 21222 = 2 × × 131, so it is divisible by 2.
What are the factors of 21222?
1, 2, 3, 6, 9, 18, 27, 54, 81, 131, 162, 262, 393, 786, 1179, 2358, 3537, 7074, 10611, 21222.
What is 21222 in binary?
101001011100110 (hexadecimal 52E6, octal 51346).
What is the square root of 21222?
About 145.6777, exactly 9√262.
Is 21222 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 21222?
21222 is a Harshad number: divisible by its digit sum 9.