The number 21271
21271 is a composite number with 4 divisors. Its prime factorisation is 89 × 239. Divisors (4): 1, 89, 239, 21271.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21271: a semiprime: 89 × 239, the product of two primes.
- 2
21271 is composite. Its prime factorisation is
- 3
The divisors add up to 21600; without 21271 itself that is 329, so 21271 is deficient (329 is less than 21271). Euler's totient φ(21271) = 20944 numbers up to 21271 share no factor with it.
- 4
The digits of 21271 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 56 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21271 = 89 \times 239 \]
21271 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 21600 |
| Euler totient φ(n) | 20944 |
| Square | 452455441 |
| Cube | 9624179685511 |
| Square root | 145.845809 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 56 |
| Scientific notation | 2.1271 × |
21271 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand two hundred and seventy-one |
| Binary (base 2) | 101001100010111 |
| Octal (base 8) | 51427 |
| Hexadecimal (base 16) | 5317 |
| Base 3 | 1002011211 |
| As time | 21271 seconds = 5 h 54 min 31 s |
Is 21271 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 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 5) | 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 4) | 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 8) | 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 21271 a prime number?
No. 21271 = 89 × 239, so it is divisible by 89.
What are the factors of 21271?
1, 89, 239, 21271.
What is 21271 in binary?
101001100010111 (hexadecimal 5317, octal 51427).
What is the square root of 21271?
About 145.8458.
Is 21271 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 21271?
21271 is a semiprime: 89 × 239, the product of two primes.