The number 21737
21737 is a twin prime (21737 and 21739 are both prime) and the 2438th prime number. Its only divisors are 1 and 21737.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21737: a twin prime (21737 and 21739 are both prime); the 2438th prime number.
- 2
21737 is prime, so its only factors are 1 and 21737. It is the 2438th prime; the next prime is 21739 and the one before is 21727.
- 3
The divisors add up to 21738; without 21737 itself that is 1, so 21737 is deficient (1 is less than 21737). Euler's totient φ(21737) = 21736 numbers up to 21737 share no factor with it.
- 4
The digits of 21737 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 162 steps to reach 1.
21737 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 21738 |
| Euler totient φ(n) | 21736 |
| Square | 472497169 |
| Cube | 10270670962553 |
| Square root | 147.434731 |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 162 |
| Scientific notation | 2.1737 × |
21737 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand seven hundred and thirty-seven |
| Binary (base 2) | 101010011101001 |
| Octal (base 8) | 52351 |
| Hexadecimal (base 16) | 54E9 |
| Base 3 | 1002211002 |
| As time | 21737 seconds = 6 h 2 min 17 s |
Is 21737 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 2) | 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 2) | 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 1) | 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 7) | 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 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21737 a prime number?
Yes. 21737 is divisible only by 1 and itself.
What are the factors of 21737?
1, 21737.
What is 21737 in binary?
101010011101001 (hexadecimal 54E9, octal 52351).
What is the square root of 21737?
About 147.4347.
Is 21737 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 21737?
21737 is a twin prime (21737 and 21739 are both prime); the 2438th prime number.