The number 21471
21471 is a composite number with 8 divisors. Its prime factorisation is 3 × 17 × 421. Divisors (8): 1, 3, 17, 51, 421, 1263, 7157, 21471.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21471 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21471 is composite. Its prime factorisation is
- 3
The divisors add up to 30384; without 21471 itself that is 8913, so 21471 is deficient (8913 is less than 21471). Euler's totient φ(21471) = 13440 numbers up to 21471 share no factor with it.
- 4
The digits of 21471 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 87 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21471 = 3 \times 17 \times 421 \]
21471 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 30384 |
| Euler totient φ(n) | 13440 |
| Square | 461003841 |
| Cube | 9898213470111 |
| Square root | 146.529860 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 87 |
| Scientific notation | 2.1471 × |
21471 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and seventy-one |
| Binary (base 2) | 101001111011111 |
| Octal (base 8) | 51737 |
| Hexadecimal (base 16) | 53DF |
| Base 3 | 1002110020 |
| As time | 21471 seconds = 5 h 57 min 51 s |
Is 21471 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 | Yes (21471 ÷ 3 = 7157) | 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 3) | 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 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 6) | 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 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21471 a prime number?
No. 21471 = 3 × 17 × 421, so it is divisible by 3.
What are the factors of 21471?
1, 3, 17, 51, 421, 1263, 7157, 21471.
What is 21471 in binary?
101001111011111 (hexadecimal 53DF, octal 51737).
What is the square root of 21471?
About 146.5299.
Is 21471 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 21471?
It is a composite number with 8 divisors.