The number 21164
21164 is a composite number with 24 divisors. Its prime factorisation is × 11 × 13 × 37. Divisors (24): 1, 2, 4, 11, 13, 22, 26, 37, 44, 52, 74, 143, 148, 286, 407, 481 … 21164.
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How to work it out
- 1
21164 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21164 is composite. Its prime factorisation is
- 3
The divisors add up to 44688; without 21164 itself that is 23524, so 21164 is abundant (23524 is more than 21164). Euler's totient φ(21164) = 8640 numbers up to 21164 share no factor with it.
- 4
The digits of 21164 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21164 = 2^{2} \times 11 \times 13 \times 37 \]21164 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 44688 |
| Euler totient φ(n) | 8640 |
| Square | 447914896 |
| Cube | 9479670858944 |
| Square root | 145.478521 (= 2√5291) |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1164 × |
21164 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and sixty-four |
| Binary (base 2) | 101001010101100 |
| Octal (base 8) | 51254 |
| Hexadecimal (base 16) | 52AC |
| Base 3 | 1002000212 |
| As time | 21164 seconds = 5 h 52 min 44 s |
Is 21164 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21164 ÷ 2 = 10582) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21164 ÷ 4 = 5291) | 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 | No (remainder 2) | 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 | No (remainder 5) | 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 | Yes (21164 ÷ 11 = 1924) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21164 a prime number?
No. 21164 = × 11 × 13 × 37, so it is divisible by 2.
What are the factors of 21164?
1, 2, 4, 11, 13, 22, 26, 37, 44, 52, 74, 143, 148, 286, 407, 481, 572, 814, 962, 1628, 1924, 5291, 10582, 21164.
What is 21164 in binary?
101001010101100 (hexadecimal 52AC, octal 51254).
What is the square root of 21164?
About 145.4785, exactly 2√5291.
Is 21164 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 21164?
It is a composite number with 24 divisors.