The number 21276
21276 is a composite number with 24 divisors. Its prime factorisation is × × 197. Divisors (24): 1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108, 197, 394, 591, 788 … 21276.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21276: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.
- 2
21276 is composite. Its prime factorisation is
- 3
The divisors add up to 55440; without 21276 itself that is 34164, so 21276 is abundant (34164 is more than 21276). Euler's totient φ(21276) = 7056 numbers up to 21276 share no factor with it.
- 4
The digits of 21276 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21276 = 2^{2} \times 3^{3} \times 197 \]21276 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 55440 |
| Euler totient φ(n) | 7056 |
| Square | 452668176 |
| Cube | 9630968112576 |
| Square root | 145.862949 (= 6√591) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1276 × |
21276 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand two hundred and seventy-six |
| Binary (base 2) | 101001100011100 |
| Octal (base 8) | 51434 |
| Hexadecimal (base 16) | 531C |
| Base 3 | 1002012000 |
| As time | 21276 seconds = 5 h 54 min 36 s |
Is 21276 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21276 ÷ 2 = 10638) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21276 ÷ 3 = 7092) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21276 ÷ 4 = 5319) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | Yes (21276 ÷ 6 = 3546) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 3) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (21276 ÷ 9 = 2364) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 6) | 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 (21276 ÷ 12 = 1773) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21276 a prime number?
No. 21276 = × × 197, so it is divisible by 2.
What are the factors of 21276?
1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108, 197, 394, 591, 788, 1182, 1773, 2364, 3546, 5319, 7092, 10638, 21276.
What is 21276 in binary?
101001100011100 (hexadecimal 531C, octal 51434).
What is the square root of 21276?
About 145.8629, exactly 6√591.
Is 21276 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 21276?
21276 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.