The number 21773
21773 is the 2443rd prime number. Its only divisors are 1 and 21773.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21773: the 2443rd prime number.
- 2
21773 is prime, so its only factors are 1 and 21773. It is the 2443rd prime; the next prime is 21787 and the one before is 21767.
- 3
The divisors add up to 21774; without 21773 itself that is 1, so 21773 is deficient (1 is less than 21773). Euler's totient φ(21773) = 21772 numbers up to 21773 share no factor with it.
- 4
The digits of 21773 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 69 steps to reach 1.
21773 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 21774 |
| Euler totient φ(n) | 21772 |
| Square | 474063529 |
| Cube | 10321785216917 |
| Square root | 147.556769 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 69 |
| Scientific notation | 2.1773 × |
21773 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand seven hundred and seventy-three |
| Binary (base 2) | 101010100001101 |
| Octal (base 8) | 52415 |
| Hexadecimal (base 16) | 550D |
| Base 3 | 1002212102 |
| As time | 21773 seconds = 6 h 2 min 53 s |
Is 21773 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 | No (remainder 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 5) | 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 4) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21773 a prime number?
Yes. 21773 is divisible only by 1 and itself.
What are the factors of 21773?
1, 21773.
What is 21773 in binary?
101010100001101 (hexadecimal 550D, octal 52415).
What is the square root of 21773?
About 147.5568.
Is 21773 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 21773?
21773 is the 2443rd prime number.