The number 21136
21136 is a composite number with 10 divisors. Its prime factorisation is × 1321. Divisors (10): 1, 2, 4, 8, 16, 1321, 2642, 5284, 10568, 21136.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21136 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21136 is composite. Its prime factorisation is
- 3
The divisors add up to 40982; without 21136 itself that is 19846, so 21136 is deficient (19846 is less than 21136). Euler's totient φ(21136) = 10560 numbers up to 21136 share no factor with it.
- 4
The digits of 21136 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 105 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21136 = 2^{4} \times 1321 \]21136 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 10 |
| Sum of divisors | 40982 |
| Euler totient φ(n) | 10560 |
| Square | 446730496 |
| Cube | 9442095763456 |
| Square root | 145.382255 (= 4√1321) |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 105 |
| Scientific notation | 2.1136 × |
21136 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand one hundred and thirty-six |
| Binary (base 2) | 101001010010000 |
| Octal (base 8) | 51220 |
| Hexadecimal (base 16) | 5290 |
| Base 3 | 1001222211 |
| As time | 21136 seconds = 5 h 52 min 16 s |
Is 21136 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21136 ÷ 2 = 10568) | 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 (21136 ÷ 4 = 5284) | 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 3) | 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 | Yes (21136 ÷ 8 = 2642) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 4) | 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 5) | 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 21136 a prime number?
No. 21136 = × 1321, so it is divisible by 2.
What are the factors of 21136?
1, 2, 4, 8, 16, 1321, 2642, 5284, 10568, 21136.
What is 21136 in binary?
101001010010000 (hexadecimal 5290, octal 51220).
What is the square root of 21136?
About 145.3823, exactly 4√1321.
Is 21136 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 21136?
It is a composite number with 10 divisors.