The number 20749
20749 is a twin prime (20747 and 20749 are both prime) and the 2337th prime number. Its only divisors are 1 and 20749.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 20749: a twin prime (20747 and 20749 are both prime); the 2337th prime number.
- 2
20749 is prime, so its only factors are 1 and 20749. It is the 2337th prime; the next prime is 20753 and the one before is 20747.
- 3
The divisors add up to 20750; without 20749 itself that is 1, so 20749 is deficient (1 is less than 20749). Euler's totient φ(20749) = 20748 numbers up to 20749 share no factor with it.
- 4
The digits of 20749 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 43 steps to reach 1.
20749 at a glance
| Property | Value |
|---|---|
| Type | prime |
| Number of divisors | 2 |
| Sum of divisors | 20750 |
| Euler totient φ(n) | 20748 |
| Square | 430521001 |
| Cube | 8932880249749 |
| Square root | 144.045132 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 43 |
| Scientific notation | 2.0749 × |
20749 in other forms
| Form | Value |
|---|---|
| In words | twenty thousand seven hundred and forty-nine |
| Binary (base 2) | 101000100001101 |
| Octal (base 8) | 50415 |
| Hexadecimal (base 16) | 510D |
| Base 3 | 1001110111 |
| As time | 20749 seconds = 5 h 45 min 49 s |
Is 20749 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 1) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | 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 1) | 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 4) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 3) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 20749 a prime number?
Yes. 20749 is divisible only by 1 and itself.
What are the factors of 20749?
1, 20749.
What is 20749 in binary?
101000100001101 (hexadecimal 510D, octal 50415).
What is the square root of 20749?
About 144.0451.
Is 20749 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 20749?
20749 is a twin prime (20747 and 20749 are both prime); the 2337th prime number.