The number 21371
21371 is a composite number with 8 divisors. Its prime factorisation is 7 × 43 × 71. Divisors (8): 1, 7, 43, 71, 301, 497, 3053, 21371.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21371 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21371 is composite. Its prime factorisation is
- 3
The divisors add up to 25344; without 21371 itself that is 3973, so 21371 is deficient (3973 is less than 21371). Euler's totient φ(21371) = 17640 numbers up to 21371 share no factor with it.
- 4
The digits of 21371 add up to 14, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 131 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21371 = 7 \times 43 \times 71 \]
21371 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 25344 |
| Euler totient φ(n) | 17640 |
| Square | 456719641 |
| Cube | 9760555447811 |
| Square root | 146.188235 |
| Digit sum / digital root | 14 / 5 |
| Collatz steps to 1 | 131 |
| Scientific notation | 2.1371 × |
21371 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand three hundred and seventy-one |
| Binary (base 2) | 101001101111011 |
| Octal (base 8) | 51573 |
| Hexadecimal (base 16) | 537B |
| Base 3 | 1002022112 |
| As time | 21371 seconds = 5 h 56 min 11 s |
Is 21371 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 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 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21371 ÷ 7 = 3053) | 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | 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 9) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 11) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21371 a prime number?
No. 21371 = 7 × 43 × 71, so it is divisible by 7.
What are the factors of 21371?
1, 7, 43, 71, 301, 497, 3053, 21371.
What is 21371 in binary?
101001101111011 (hexadecimal 537B, octal 51573).
What is the square root of 21371?
About 146.1882.
Is 21371 divisible by 3?
No. Its digits add up to 14, which is not a multiple of 3.
What is special about the number 21371?
It is a composite number with 8 divisors.