The number 21423
21423 is a composite number with 8 divisors. Its prime factorisation is 3 × 37 × 193. Divisors (8): 1, 3, 37, 111, 193, 579, 7141, 21423.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
21423 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
21423 is composite. Its prime factorisation is
- 3
The divisors add up to 29488; without 21423 itself that is 8065, so 21423 is deficient (8065 is less than 21423). Euler's totient φ(21423) = 13824 numbers up to 21423 share no factor with it.
- 4
The digits of 21423 add up to 12, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 48 steps to reach 1.
LaTeX source of the formulas on this page
\[ 21423 = 3 \times 37 \times 193 \]
21423 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 29488 |
| Euler totient φ(n) | 13824 |
| Square | 458944929 |
| Cube | 9831977213967 |
| Square root | 146.365980 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 48 |
| Scientific notation | 2.1423 × |
21423 in other forms
| Form | Value |
|---|---|
| In words | twenty-one thousand four hundred and twenty-three |
| Binary (base 2) | 101001110101111 |
| Octal (base 8) | 51657 |
| Hexadecimal (base 16) | 53AF |
| Base 3 | 1002101110 |
| As time | 21423 seconds = 5 h 57 min 3 s |
Is 21423 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 (21423 ÷ 3 = 7141) | 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 | No (remainder 3) | 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 6) | 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 21423 a prime number?
No. 21423 = 3 × 37 × 193, so it is divisible by 3.
What are the factors of 21423?
1, 3, 37, 111, 193, 579, 7141, 21423.
What is 21423 in binary?
101001110101111 (hexadecimal 53AF, octal 51657).
What is the square root of 21423?
About 146.3660.
Is 21423 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 21423?
It is a composite number with 8 divisors.