The number 28423
28423 is a composite number with 4 divisors. Its prime factorisation is 43 × 661. Divisors (4): 1, 43, 661, 28423.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 28423: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 43 × 661, the product of two primes.
- 2
28423 is composite. Its prime factorisation is
- 3
The divisors add up to 29128; without 28423 itself that is 705, so 28423 is deficient (705 is less than 28423). Euler's totient φ(28423) = 27720 numbers up to 28423 share no factor with it.
- 4
The digits of 28423 add up to 19, and repeating that until one digit is left gives the digital root 1. The Collatz sequence (halve if even, else 3n+1) takes 90 steps to reach 1.
LaTeX source of the formulas on this page
\[ 28423 = 43 \times 661 \]
28423 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 29128 |
| Euler totient φ(n) | 27720 |
| Square | 807866929 |
| Cube | 22962001722967 |
| Square root | 168.591222 |
| Digit sum / digital root | 19 / 1 |
| Collatz steps to 1 | 90 |
| Scientific notation | 2.8423 × |
28423 in other forms
| Form | Value |
|---|---|
| In words | twenty-eight thousand four hundred and twenty-three |
| Binary (base 2) | 110111100000111 |
| Octal (base 8) | 67407 |
| Hexadecimal (base 16) | 6F07 |
| Base 3 | 1102222201 |
| As time | 28423 seconds = 7 h 53 min 43 s |
Is 28423 divisible by 2 to 12?
| Divisor | Answer | Rule |
|---|---|---|
| 2 | No (remainder 1) | 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 | No (remainder 3) | 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 1) | 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 | No (remainder 7) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 1) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 10) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 28423 a prime number?
No. 28423 = 43 × 661, so it is divisible by 43.
What are the factors of 28423?
1, 43, 661, 28423.
What is 28423 in binary?
110111100000111 (hexadecimal 6F07, octal 67407).
What is the square root of 28423?
About 168.5912.
Is 28423 divisible by 3?
No. Its digits add up to 19, which is not a multiple of 3.
What is special about the number 28423?
28423 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 43 × 661, the product of two primes.