The number 21727
21727 is the 2437th prime number. Its only divisors are 1 and 21727.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21727: the 2437th prime number.
- 2
21727 is prime, so its only factors are 1 and 21727. It is the 2437th prime; the next prime is 21737 and the one before is 21713.
- 3
The divisors add up to 21728; without 21727 itself that is 1, so 21727 is deficient (1 is less than 21727). Euler's totient φ(21727) = 21726 numbers up to 21727 share no factor with it.
- 4
The digits of 21727 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 100 steps to reach 1.
21727 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 21728 |
| Euler totient φ(n) | 21726 |
| Square | 472062529 |
| Cube | 10256502567583 |
| Square root | 147.400814 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1727 × |
21727 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand seven hundred and twenty-seven |
| Binary (base 2) | 101010011011111 |
| Octal (base 8) | 52337 |
| Hexadecimal (base 16) | 54DF |
| Base 3 | 1002210201 |
| As time | 21727 seconds = 6 h 2 min 7 s |
Is 21727 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 1) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 2) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 6) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 7) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21727 a prime number?
Yes. 21727 is divisible only by 1 and itself.
What are the factors of 21727?
1, 21727.
What is 21727 in binary?
101010011011111 (hexadecimal 54DF, octal 52337).
What is the square root of 21727?
About 147.4008.
Is 21727 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 21727?
21727 is the 2437th prime number.