The number 21022
21022 is a composite number with 8 divisors. Its prime factorisation is 2 × 23 × 457. Divisors (8): 1, 2, 23, 46, 457, 914, 10511, 21022.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21022: a happy number: repeatedly adding the squares of its digits reaches 1.
- 2
21022 is composite. Its prime factorisation is
- 3
The divisors add up to 32976; without 21022 itself that is 11954, so 21022 is deficient (11954 is less than 21022). Euler's totient φ(21022) = 10032 numbers up to 21022 share no factor with it.
- 4
The digits of 21022 add up to 7, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 87 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21022 = 2 \times 23 \times 457 \]
21022 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 32976 |
| Euler totient φ(n) | 10032 |
| Square | 441924484 |
| Cube | 9290136502648 |
| Square root | 144.989655 |
| Digit sum / digital root | 7 / 7 |
| Collatz steps to 1 | 87 |
| Scientific notation | 2.1022 × |
21022 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and twenty-two |
| Binary (base 2) | 101001000011110 |
| Octal (base 8) | 51036 |
| Hexadecimal (base 16) | 521E |
| Base 3 | 1001211121 |
| As time | 21022 seconds = 5 h 50 min 22 s |
Is 21022 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21022 ÷ 2 = 10511) | 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 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 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 1) | 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 | No (remainder 7) | 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 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21022 a prime number?
No. 21022 = 2 × 23 × 457, so it is divisible by 2.
What are the factors of 21022?
1, 2, 23, 46, 457, 914, 10511, 21022.
What is 21022 in binary?
101001000011110 (hexadecimal 521E, octal 51036).
What is the square root of 21022?
About 144.9897.
Is 21022 divisible by 3?
No. Its digits add up to 7, which is not a multiple of 3.
What is special about the number 21022?
21022 is a happy number: repeatedly adding the squares of its digits reaches 1.