The number 21436
21436 is a composite number with 12 divisors. Its prime factorisation is × 23 × 233. Divisors (12): 1, 2, 4, 23, 46, 92, 233, 466, 932, 5359, 10718, 21436.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21436 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21436 is composite. Its prime factorisation is
- 3
The divisors add up to 39312; without 21436 itself that is 17876, so 21436 is deficient (17876 is less than 21436). Euler's totient φ(21436) = 10208 numbers up to 21436 share no factor with it.
- 4
The digits of 21436 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 193 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21436 = 2^{2} \times 23 \times 233 \]21436 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 12 |
| Sum of divisors | 39312 |
| Euler totient φ(n) | 10208 |
| Square | 459502096 |
| Cube | 9849886929856 |
| Square root | 146.410382 (= 2√5359) |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 193 |
| Scientific notation | 2.1436 × |
21436 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and thirty-six |
| Binary (base 2) | 101001110111100 |
| Octal (base 8) | 51674 |
| Hexadecimal (base 16) | 53BC |
| Base 3 | 1002101221 |
| As time | 21436 seconds = 5 h 57 min 16 s |
Is 21436 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21436 ÷ 2 = 10718) | 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 | Yes (21436 ÷ 4 = 5359) | 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 4) | 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 4) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 6) | 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 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 21436 a prime number?
No. 21436 = × 23 × 233, so it is divisible by 2.
What are the factors of 21436?
1, 2, 4, 23, 46, 92, 233, 466, 932, 5359, 10718, 21436.
What is 21436 in binary?
101001110111100 (hexadecimal 53BC, octal 51674).
What is the square root of 21436?
About 146.4104, exactly 2√5359.
Is 21436 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 21436?
It is a composite number with 12 divisors.