The number 42009
42009 is a composite number with 16 divisors. Its prime factorisation is 3 × 11 × 19 × 67. Divisors (16): 1, 3, 11, 19, 33, 57, 67, 201, 209, 627, 737, 1273, 2211, 3819, 14003, 42009.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
42009 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
42009 is composite. Its prime factorisation is
- 3
The divisors add up to 65280; without 42009 itself that is 23271, so 42009 is deficient (23271 is less than 42009). Euler's totient φ(42009) = 23760 numbers up to 42009 share no factor with it.
- 4
The digits of 42009 add up to 15, and repeating that until one digit is left gives the digital root 6. The Collatz sequence (halve if even, else 3n+1) takes 106 steps to reach 1.
LaTeX source of the formulas on this page
\[ 42009 = 3 \times 11 \times 19 \times 67 \]
42009 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 16 |
| Sum of divisors | 65280 |
| Euler totient φ(n) | 23760 |
| Square | 1764756081 |
| Cube | 74135638206729 |
| Square root | 204.960972 |
| Digit sum / digital root | 15 / 6 |
| Collatz steps to 1 | 106 |
| Scientific notation | 4.2009 × |
42009 in other forms
| Form | Value |
|---|---|
| In words | forty-two thousand and nine |
| Binary (base 2) | 1010010000011001 |
| Octal (base 8) | 122031 |
| Hexadecimal (base 16) | A419 |
| Base 3 | 2010121220 |
| As time | 42009 seconds = 11 h 40 min 9 s |
Is 42009 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 (42009 ÷ 3 = 14003) | 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 3) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 2) | 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 6) | 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 | Yes (42009 ÷ 11 = 3819) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 42009 a prime number?
No. 42009 = 3 × 11 × 19 × 67, so it is divisible by 3.
What are the factors of 42009?
1, 3, 11, 19, 33, 57, 67, 201, 209, 627, 737, 1273, 2211, 3819, 14003, 42009.
What is 42009 in binary?
1010010000011001 (hexadecimal A419, octal 122031).
What is the square root of 42009?
About 204.9610.
Is 42009 divisible by 3?
Yes. Its digits add up to 15, a multiple of 3.
What is special about the number 42009?
It is a composite number with 16 divisors.