The number 15824
15824 is a composite number with 20 divisors. Its prime factorisation is × 23 × 43. Divisors (20): 1, 2, 4, 8, 16, 23, 43, 46, 86, 92, 172, 184, 344, 368, 688, 989 … 15824.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
15824 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
15824 is composite. Its prime factorisation is
- 3
The divisors add up to 32736; without 15824 itself that is 16912, so 15824 is abundant (16912 is more than 15824). Euler's totient φ(15824) = 7392 numbers up to 15824 share no factor with it.
- 4
The digits of 15824 add up to 20, and repeating that until one digit is left gives the digital root 2. The Collatz sequence (halve if even, else 3n+1) takes 53 steps to reach 1.
LaTeX source of the formulas on this page
\[ 15824 = 2^{4} \times 23 \times 43 \]15824 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 20 |
| Sum of divisors | 32736 |
| Euler totient φ(n) | 7392 |
| Square | 250398976 |
| Cube | 3962313396224 |
| Square root | 125.793482 (= 4√989) |
| Digit sum / digital root | 20 / 2 |
| Collatz steps to 1 | 53 |
| Scientific notation | 1.5824 × |
15824 in other forms
| Form | Value |
|---|---|
| In words | fifteen thousand eight hundred and twenty-four |
| Binary (base 2) | 11110111010000 |
| Octal (base 8) | 36720 |
| Hexadecimal (base 16) | 3DD0 |
| Base 3 | 210201002 |
| As time | 15824 seconds = 4 h 23 min 44 s |
Is 15824 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (15824 ÷ 2 = 7912) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | No (remainder 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (15824 ÷ 4 = 3956) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 4) | A number is divisible by 5 if the last digit is 0 or 5. |
| 6 | No (remainder 2) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 (15824 ÷ 8 = 1978) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 2) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 4) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 6) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 8) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 15824 a prime number?
No. 15824 = × 23 × 43, so it is divisible by 2.
What are the factors of 15824?
1, 2, 4, 8, 16, 23, 43, 46, 86, 92, 172, 184, 344, 368, 688, 989, 1978, 3956, 7912, 15824.
What is 15824 in binary?
11110111010000 (hexadecimal 3DD0, octal 36720).
What is the square root of 15824?
About 125.7935, exactly 4√989.
Is 15824 divisible by 3?
No. Its digits add up to 20, which is not a multiple of 3.
What is special about the number 15824?
It is a composite number with 20 divisors.