The number 21411
21411 is a composite number with 16 divisors. Its prime factorisation is × 13 × 61. Divisors (16): 1, 3, 9, 13, 27, 39, 61, 117, 183, 351, 549, 793, 1647, 2379, 7137, 21411.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 21411: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.
- 2
21411 is composite. Its prime factorisation is
- 3
The divisors add up to 34720; without 21411 itself that is 13309, so 21411 is deficient (13309 is less than 21411). Euler's totient φ(21411) = 12960 numbers up to 21411 share no factor with it.
- 4
The digits of 21411 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 48 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21411 = 3^{3} \times 13 \times 61 \]21411 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 34720 |
| Euler totient φ(n) | 12960 |
| Square | 458430921 |
| Cube | 9815464449531 |
| Square root | 146.324981 (= 3√2379) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 48 |
| Scientific notation | 2.1411 × |
21411 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and eleven |
| Binary (base 2) | 101001110100011 |
| Octal (base 8) | 51643 |
| Hexadecimal (base 16) | 53A3 |
| Base 3 | 1002101000 |
| As time | 21411 seconds = 5 h 56 min 51 s |
Is 21411 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 (21411 ÷ 3 = 7137) | 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 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 3) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | Yes (21411 ÷ 9 = 2379) | 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 5) | 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 21411 a prime number?
No. 21411 = × 13 × 61, so it is divisible by 3.
What are the factors of 21411?
1, 3, 9, 13, 27, 39, 61, 117, 183, 351, 549, 793, 1647, 2379, 7137, 21411.
What is 21411 in binary?
101001110100011 (hexadecimal 53A3, octal 51643).
What is the square root of 21411?
About 146.3250, exactly 3√2379.
Is 21411 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 21411?
21411 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 9.