The number 27721
27721 is a composite number with 4 divisors. Its prime factorisation is 19 × 1459. Divisors (4): 1, 19, 1459, 27721.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 27721: a Harshad number: divisible by its digit sum 19; a semiprime: 19 × 1459, the product of two primes.
- 2
27721 is composite. Its prime factorisation is
- 3
The divisors add up to 29200; without 27721 itself that is 1479, so 27721 is deficient (1479 is less than 27721). Euler's totient φ(27721) = 26244 numbers up to 27721 share no factor with it.
- 4
The digits of 27721 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 90 steps to reach 1.
LaTeX source of the formulas on this page
\[ 27721 = 19 \times 1459 \]
27721 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 29200 |
| Euler totient φ(n) | 26244 |
| Square | 768453841 |
| Cube | 21302308926361 |
| Square root | 166.496246 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 90 |
| Scientific notation | 2.7721 × |
27721 in other forms
| Form | Value |
|---|---|
| In words | twenty-seven thousand seven hundred and twenty-one |
| Binary (base 2) | 110110001001001 |
| Octal (base 8) | 66111 |
| Hexadecimal (base 16) | 6C49 |
| Base 3 | 1102000201 |
| As time | 27721 seconds = 7 h 42 min 1 s |
Is 27721 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 1) | 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 1) | 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 1) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 27721 a prime number?
No. 27721 = 19 × 1459, so it is divisible by 19.
What are the factors of 27721?
1, 19, 1459, 27721.
What is 27721 in binary?
110110001001001 (hexadecimal 6C49, octal 66111).
What is the square root of 27721?
About 166.4962.
Is 27721 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 27721?
27721 is a Harshad number: divisible by its digit sum 19; a semiprime: 19 × 1459, the product of two primes.