The number 21492
21492 is a composite number with 24 divisors. Its prime factorisation is × × 199. Divisors (24): 1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108, 199, 398, 597, 796 … 21492.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21492: a Harshad number: divisible by its digit sum 18.
- 2
21492 is composite. Its prime factorisation is
- 3
The divisors add up to 56000; without 21492 itself that is 34508, so 21492 is abundant (34508 is more than 21492). Euler's totient φ(21492) = 7128 numbers up to 21492 share no factor with it.
- 4
The digits of 21492 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 100 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21492 = 2^{2} \times 3^{3} \times 199 \]21492 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 56000 |
| Euler totient φ(n) | 7128 |
| Square | 461906064 |
| Cube | 9927285127488 |
| Square root | 146.601501 (= 6√597) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1492 × |
21492 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and ninety-two |
| Binary (base 2) | 101001111110100 |
| Octal (base 8) | 51764 |
| Hexadecimal (base 16) | 53F4 |
| Base 3 | 1002111000 |
| As time | 21492 seconds = 5 h 58 min 12 s |
Is 21492 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21492 ÷ 2 = 10746) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21492 ÷ 3 = 7164) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21492 ÷ 4 = 5373) | 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 (21492 ÷ 6 = 3582) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 (21492 ÷ 9 = 2388) | 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 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (21492 ÷ 12 = 1791) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21492 a prime number?
No. 21492 = × × 199, so it is divisible by 2.
What are the factors of 21492?
1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108, 199, 398, 597, 796, 1194, 1791, 2388, 3582, 5373, 7164, 10746, 21492.
What is 21492 in binary?
101001111110100 (hexadecimal 53F4, octal 51764).
What is the square root of 21492?
About 146.6015, exactly 6√597.
Is 21492 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 21492?
21492 is a Harshad number: divisible by its digit sum 18.