The number 423
423 is a composite number with 6 divisors. Its prime factorisation is × 47. Divisors (6): 1, 3, 9, 47, 141, 423.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 423: a Harshad number: divisible by its digit sum 9.
- 2
423 is composite. Its prime factorisation is
- 3
The divisors add up to 624; without 423 itself that is 201, so 423 is deficient (201 is less than 423). Euler's totient φ(423) = 276 numbers up to 423 share no factor with it.
- 4
The digits of 423 add up to 9, and repeating that until one digit is left gives the digital root 9. The Collatz sequence (halve if even, else 3n+1) takes 32 steps to reach 1.
LaTeX source of the formulas on this page
\[ 423 = 3^{2} \times 47 \]423 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 6 |
| Sum of divisors | 624 |
| Euler totient φ(n) | 276 |
| Square | 178929 |
| Cube | 75686967 |
| Square root | 20.566964 (= 3√47) |
| Digit sum / digital root | 9 / 9 |
| Collatz steps to 1 | 32 |
| Scientific notation | 4.23 × |
423 in other forms
| Form | Value |
|---|---|
| In words | four hundred and twenty-three |
| Roman numerals | CDXXIII |
| Binary (base 2) | 110100111 |
| Octal (base 8) | 647 |
| Hexadecimal (base 16) | 1A7 |
| Base 3 | 120200 |
| As time | 423 seconds = 7 min 3 s |
Is 423 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 | Yes (423 ÷ 3 = 141) | 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 3) | 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 | Yes (423 ÷ 9 = 47) | 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 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 3) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 423 a prime number?
No. 423 = × 47, so it is divisible by 3.
What are the factors of 423?
1, 3, 9, 47, 141, 423.
What is 423 in binary?
110100111 (hexadecimal 1A7, octal 647).
What is the square root of 423?
About 20.5670, exactly 3√47.
What is 423 in Roman numerals?
CDXXIII.
Is 423 divisible by 3?
Yes. Its digits add up to 9, a multiple of 3.
What is special about the number 423?
423 is a Harshad number: divisible by its digit sum 9.