The number 28408
28408 is a composite number with 16 divisors. Its prime factorisation is × 53 × 67. Divisors (16): 1, 2, 4, 8, 53, 67, 106, 134, 212, 268, 424, 536, 3551, 7102, 14204, 28408.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
28408 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
28408 is composite. Its prime factorisation is
- 3
The divisors add up to 55080; without 28408 itself that is 26672, so 28408 is deficient (26672 is less than 28408). Euler's totient φ(28408) = 13728 numbers up to 28408 share no factor with it.
- 4
The digits of 28408 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 90 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28408 = 2^{3} \times 53 \times 67 \]28408 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 55080 |
| Euler totient φ(n) | 13728 |
| Square | 807014464 |
| Cube | 22925666893312 |
| Square root | 168.546729 (= 2√7102) |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 90 |
| Scientific notation | 2.8408 × |
28408 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand four hundred and eight |
| Binary (base 2) | 110111011111000 |
| Octal (base 8) | 67370 |
| Hexadecimal (base 16) | 6EF8 |
| Base 3 | 1102222011 |
| As time | 28408 seconds = 7 h 53 min 28 s |
Is 28408 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (28408 ÷ 2 = 14204) | 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 (28408 ÷ 4 = 7102) | 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 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 | Yes (28408 ÷ 8 = 3551) | 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 8) | 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 4) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28408 a prime number?
No. 28408 = × 53 × 67, so it is divisible by 2.
What are the factors of 28408?
1, 2, 4, 8, 53, 67, 106, 134, 212, 268, 424, 536, 3551, 7102, 14204, 28408.
What is 28408 in binary?
110111011111000 (hexadecimal 6EF8, octal 67370).
What is the square root of 28408?
About 168.5467, exactly 2√7102.
Is 28408 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 28408?
It is a composite number with 16 divisors.