The number 42809
42809 is a composite number with 8 divisors. Its prime factorisation is 13 × 37 × 89. Divisors (8): 1, 13, 37, 89, 481, 1157, 3293, 42809.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42809 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42809 is composite. Its prime factorisation is
- 3
The divisors add up to 47880; without 42809 itself that is 5071, so 42809 is deficient (5071 is less than 42809). Euler's totient φ(42809) = 38016 numbers up to 42809 share no factor with it.
- 4
The digits of 42809 add up to 23, and repeating that until one digit is left gives the digital root 5. The Collatz sequence (halve if even, else 3n+1) takes 194 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42809 = 13 \times 37 \times 89 \]
42809 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 47880 |
| Euler totient φ(n) | 38016 |
| Square | 1832610481 |
| Cube | 78452222081129 |
| Square root | 206.903359 |
| Digit sum / digital root | 23 / 5 |
| Collatz steps to 1 | 194 |
| Scientific notation | 4.2809 × |
42809 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand eight hundred and nine |
| Binary (base 2) | 1010011100111001 |
| Octal (base 8) | 123471 |
| Hexadecimal (base 16) | A739 |
| Base 3 | 2011201112 |
| As time | 42809 seconds = 11 h 53 min 29 s |
Is 42809 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 2) | A number is divisible by 3 if the digits add up to a multiple of 3. |
| 4 | No (remainder 1) | 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 | No (remainder 5) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 4) | 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 1) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 5) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 9) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 8) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 5) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42809 a prime number?
No. 42809 = 13 × 37 × 89, so it is divisible by 13.
What are the factors of 42809?
1, 13, 37, 89, 481, 1157, 3293, 42809.
What is 42809 in binary?
1010011100111001 (hexadecimal A739, octal 123471).
What is the square root of 42809?
About 206.9034.
Is 42809 divisible by 3?
No. Its digits add up to 23, which is not a multiple of 3.
What is special about the number 42809?
It is a composite number with 8 divisors.