The number 21144
21144 is a composite number with 16 divisors. Its prime factorisation is × 3 × 881. Divisors (16): 1, 2, 3, 4, 6, 8, 12, 24, 881, 1762, 2643, 3524, 5286, 7048, 10572, 21144.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21144: a Harshad number: divisible by its digit sum 12.
- 2
21144 is composite. Its prime factorisation is
- 3
The divisors add up to 52920; without 21144 itself that is 31776, so 21144 is abundant (31776 is more than 21144). Euler's totient φ(21144) = 7040 numbers up to 21144 share no factor with it.
- 4
The digits of 21144 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 105 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21144 = 2^{3} \times 3 \times 881 \]21144 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 52920 |
| Euler totient φ(n) | 7040 |
| Square | 447068736 |
| Cube | 9452821353984 |
| Square root | 145.409766 (= 2√5286) |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 105 |
| Scientific notation | 2.1144 × |
21144 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and forty-four |
| Binary (base 2) | 101001010011000 |
| Octal (base 8) | 51230 |
| Hexadecimal (base 16) | 5298 |
| Base 3 | 1002000010 |
| As time | 21144 seconds = 5 h 52 min 24 s |
Is 21144 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21144 ÷ 2 = 10572) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21144 ÷ 3 = 7048) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21144 ÷ 4 = 5286) | 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 | Yes (21144 ÷ 6 = 3524) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 (21144 ÷ 8 = 2643) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 3) | 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 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (21144 ÷ 12 = 1762) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21144 a prime number?
No. 21144 = × 3 × 881, so it is divisible by 2.
What are the factors of 21144?
1, 2, 3, 4, 6, 8, 12, 24, 881, 1762, 2643, 3524, 5286, 7048, 10572, 21144.
What is 21144 in binary?
101001010011000 (hexadecimal 5298, octal 51230).
What is the square root of 21144?
About 145.4098, exactly 2√5286.
Is 21144 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 21144?
21144 is a Harshad number: divisible by its digit sum 12.