The number 21084
21084 is a composite number with 24 divisors. Its prime factorisation is × 3 × 7 × 251. Divisors (24): 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84, 251, 502, 753, 1004 … 21084.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21084 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21084 is composite. Its prime factorisation is
- 3
The divisors add up to 56448; without 21084 itself that is 35364, so 21084 is abundant (35364 is more than 21084). Euler's totient φ(21084) = 6000 numbers up to 21084 share no factor with it.
- 4
The digits of 21084 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21084 = 2^{2} \times 3 \times 7 \times 251 \]21084 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 56448 |
| Euler totient φ(n) | 6000 |
| Square | 444535056 |
| Cube | 9372577120704 |
| Square root | 145.203306 (= 2√5271) |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1084 × |
21084 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand and eighty-four |
| Binary (base 2) | 101001001011100 |
| Octal (base 8) | 51134 |
| Hexadecimal (base 16) | 525C |
| Base 3 | 1001220220 |
| As time | 21084 seconds = 5 h 51 min 24 s |
Is 21084 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21084 ÷ 2 = 10542) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21084 ÷ 3 = 7028) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21084 ÷ 4 = 5271) | 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 (21084 ÷ 6 = 3514) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21084 ÷ 7 = 3012) | 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 | No (remainder 6) | 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 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (21084 ÷ 12 = 1757) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21084 a prime number?
No. 21084 = × 3 × 7 × 251, so it is divisible by 2.
What are the factors of 21084?
1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84, 251, 502, 753, 1004, 1506, 1757, 3012, 3514, 5271, 7028, 10542, 21084.
What is 21084 in binary?
101001001011100 (hexadecimal 525C, octal 51134).
What is the square root of 21084?
About 145.2033, exactly 2√5271.
Is 21084 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 21084?
It is a composite number with 24 divisors.