The number 21441
21441 is a composite number with 8 divisors. Its prime factorisation is 3 × 7 × 1021. Divisors (8): 1, 3, 7, 21, 1021, 3063, 7147, 21441.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21441 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21441 is composite. Its prime factorisation is
- 3
The divisors add up to 32704; without 21441 itself that is 11263, so 21441 is deficient (11263 is less than 21441). Euler's totient φ(21441) = 12240 numbers up to 21441 share no factor with it.
- 4
The digits of 21441 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 100 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21441 = 3 \times 7 \times 1021 \]
21441 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 32704 |
| Euler totient φ(n) | 12240 |
| Square | 459716481 |
| Cube | 9856781069121 |
| Square root | 146.427456 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 100 |
| Scientific notation | 2.1441 × |
21441 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and forty-one |
| Binary (base 2) | 101001111000001 |
| Octal (base 8) | 51701 |
| Hexadecimal (base 16) | 53C1 |
| Base 3 | 1002102010 |
| As time | 21441 seconds = 5 h 57 min 21 s |
Is 21441 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 (21441 ÷ 3 = 7147) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | Yes (21441 ÷ 7 = 3063) | 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 3) | 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 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21441 a prime number?
No. 21441 = 3 × 7 × 1021, so it is divisible by 3.
What are the factors of 21441?
1, 3, 7, 21, 1021, 3063, 7147, 21441.
What is 21441 in binary?
101001111000001 (hexadecimal 53C1, octal 51701).
What is the square root of 21441?
About 146.4275.
Is 21441 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 21441?
It is a composite number with 8 divisors.