The number 28404
28404 is a composite number with 24 divisors. Its prime factorisation is × × 263. Divisors (24): 1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108, 263, 526, 789, 1052 … 28404.
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How to work it out
- 1
What is special about 28404: a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.
- 2
28404 is composite. Its prime factorisation is
- 3
The divisors add up to 73920; without 28404 itself that is 45516, so 28404 is abundant (45516 is more than 28404). Euler's totient φ(28404) = 9432 numbers up to 28404 share no factor with it.
- 4
The digits of 28404 add up to 18, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 90 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28404 = 2^{2} \times 3^{3} \times 263 \]28404 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 24 |
| Sum of divisors | 73920 |
| Euler totient φ(n) | 9432 |
| Square | 806787216 |
| Cube | 22915984083264 |
| Square root | 168.534863 (= 6√789) |
| Digit sum / digital root | 18 / 9 |
| Collatz steps to 1 | 90 |
| Scientific notation | 2.8404 × |
28404 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand four hundred and four |
| Binary (base 2) | 110111011110100 |
| Octal (base 8) | 67364 |
| Hexadecimal (base 16) | 6EF4 |
| Base 3 | 1102222000 |
| As time | 28404 seconds = 7 h 53 min 24 s |
Is 28404 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | Yes (28404 ÷ 2 = 14202) | A number is divisible by 2 if the last digit is even (0, 2, 4, 6, 8). |
| 3 | Yes (28404 ÷ 3 = 9468) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | Yes (28404 ÷ 4 = 7101) | 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 | Yes (28404 ÷ 6 = 4734) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 | Yes (28404 ÷ 9 = 3156) | 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 2) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | Yes (28404 ÷ 12 = 2367) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28404 a prime number?
No. 28404 = × × 263, so it is divisible by 2.
What are the factors of 28404?
1, 2, 3, 4, 6, 9, 12, 18, 27, 36, 54, 108, 263, 526, 789, 1052, 1578, 2367, 3156, 4734, 7101, 9468, 14202, 28404.
What is 28404 in binary?
110111011110100 (hexadecimal 6EF4, octal 67364).
What is the square root of 28404?
About 168.5349, exactly 6√789.
Is 28404 divisible by 3?
Yes. Its digits add up to 18, a multiple of 3.
What is special about the number 28404?
28404 is a happy number: repeatedly adding the squares of its digits reaches 1; a Harshad number: divisible by its digit sum 18.