The number 21516
21516 is a composite number with 24 divisors. Its prime factorisation is × 3 × 11 × 163. Divisors (24): 1, 2, 3, 4, 6, 11, 12, 22, 33, 44, 66, 132, 163, 326, 489, 652 … 21516.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21516 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21516 is composite. Its prime factorisation is
- 3
The divisors add up to 55104; without 21516 itself that is 33588, so 21516 is abundant (33588 is more than 21516). Euler's totient φ(21516) = 6480 numbers up to 21516 share no factor with it.
- 4
The digits of 21516 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 74 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21516 = 2^{2} \times 3 \times 11 \times 163 \]21516 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 55104 |
| Euler totient φ(n) | 6480 |
| Square | 462938256 |
| Cube | 9960579516096 |
| Square root | 146.683332 (= 2√5379) |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 74 |
| Scientific notation | 2.1516 × |
21516 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand five hundred and sixteen |
| Binary (base 2) | 101010000001100 |
| Octal (base 8) | 52014 |
| Hexadecimal (base 16) | 540C |
| Base 3 | 1002111220 |
| As time | 21516 seconds = 5 h 58 min 36 s |
Is 21516 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21516 ÷ 2 = 10758) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (21516 ÷ 3 = 7172) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (21516 ÷ 4 = 5379) | 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 (21516 ÷ 6 = 3586) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 6) | A number is divisible by 10 if the last digit is 0. |
| 11 | Yes (21516 ÷ 11 = 1956) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (21516 ÷ 12 = 1793) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21516 a prime number?
No. 21516 = × 3 × 11 × 163, so it is divisible by 2.
What are the factors of 21516?
1, 2, 3, 4, 6, 11, 12, 22, 33, 44, 66, 132, 163, 326, 489, 652, 978, 1793, 1956, 3586, 5379, 7172, 10758, 21516.
What is 21516 in binary?
101010000001100 (hexadecimal 540C, octal 52014).
What is the square root of 21516?
About 146.6833, exactly 2√5379.
Is 21516 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 21516?
It is a composite number with 24 divisors.