The number 21550
21550 is a composite number with 12 divisors. Its prime factorisation is 2 × × 431. Divisors (12): 1, 2, 5, 10, 25, 50, 431, 862, 2155, 4310, 10775, 21550.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21550 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21550 is composite. Its prime factorisation is
- 3
The divisors add up to 40176; without 21550 itself that is 18626, so 21550 is deficient (18626 is less than 21550). Euler's totient φ(21550) = 8600 numbers up to 21550 share no factor with it.
- 4
The digits of 21550 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 149 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21550 = 2 \times 5^{2} \times 431 \]21550 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 40176 |
| Euler totient φ(n) | 8600 |
| Square | 464402500 |
| Cube | 10007873875000 |
| Square root | 146.799183 (= 5√862) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 149 |
| Scientific notation | 2.155 × |
21550 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand five hundred and fifty |
| Binary (base 2) | 101010000101110 |
| Octal (base 8) | 52056 |
| Hexadecimal (base 16) | 542E |
| Base 3 | 1002120011 |
| As time | 21550 seconds = 5 h 59 min 10 s |
Is 21550 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21550 ÷ 2 = 10775) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 2) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | Yes (21550 ÷ 5 = 4310) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 4) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 6) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | Yes (21550 ÷ 10 = 2155) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 10) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21550 a prime number?
No. 21550 = 2 × × 431, so it is divisible by 2.
What are the factors of 21550?
1, 2, 5, 10, 25, 50, 431, 862, 2155, 4310, 10775, 21550.
What is 21550 in binary?
101010000101110 (hexadecimal 542E, octal 52056).
What is the square root of 21550?
About 146.7992, exactly 5√862.
Is 21550 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 21550?
It is a composite number with 12 divisors.