The number 21248
21248 is a composite number with 18 divisors. Its prime factorisation is × 83. Divisors (18): 1, 2, 4, 8, 16, 32, 64, 83, 128, 166, 256, 332, 664, 1328, 2656, 5312 … 21248.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21248 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21248 is composite. Its prime factorisation is
- 3
The divisors add up to 42924; without 21248 itself that is 21676, so 21248 is abundant (21676 is more than 21248). Euler's totient φ(21248) = 10496 numbers up to 21248 share no factor with it.
- 4
The digits of 21248 add up to 17, and repeating that until one digit is left gives the digital root 8. The Collatz sequence (halve if even, else 3n+1) takes 118 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21248 = 2^{8} \times 83 \]21248 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 18 |
| Sum of divisors | 42924 |
| Euler totient φ(n) | 10496 |
| Square | 451477504 |
| Cube | 9592994004992 |
| Square root | 145.766937 (= 16√83) |
| Digit sum / digital root | 17 / 8 |
| Collatz steps to 1 | 118 |
| Scientific notation | 2.1248 × |
21248 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand two hundred and forty-eight |
| Binary (base 2) | 101001100000000 |
| Octal (base 8) | 51400 |
| Hexadecimal (base 16) | 5300 |
| Base 3 | 1002010222 |
| As time | 21248 seconds = 5 h 54 min 8 s |
Is 21248 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (21248 ÷ 2 = 10624) | 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 (21248 ÷ 4 = 5312) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 3) | 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 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 (21248 ÷ 8 = 2656) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 8) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 8) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | 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 21248 a prime number?
No. 21248 = × 83, so it is divisible by 2.
What are the factors of 21248?
1, 2, 4, 8, 16, 32, 64, 83, 128, 166, 256, 332, 664, 1328, 2656, 5312, 10624, 21248.
What is 21248 in binary?
101001100000000 (hexadecimal 5300, octal 51400).
What is the square root of 21248?
About 145.7669, exactly 16√83.
Is 21248 divisible by 3?
No. Its digits add up to 17, which is not a multiple of 3.
What is special about the number 21248?
It is a composite number with 18 divisors.