The number 12009
12009 is a composite number with 4 divisors. Its prime factorisation is 3 × 4003. Divisors (4): 1, 3, 4003, 12009.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 12009: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 4003, the product of two primes.
- 2
12009 is composite. Its prime factorisation is
- 3
The divisors add up to 16016; without 12009 itself that is 4007, so 12009 is deficient (4007 is less than 12009). Euler's totient φ(12009) = 8004 numbers up to 12009 share no factor with it.
- 4
The digits of 12009 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 81 steps to reach 1.
LaTeX source of the formulas on this page
\[ 12009 = 3 \times 4003 \]
12009 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 16016 |
| Euler totient φ(n) | 8004 |
| Square | 144216081 |
| Cube | 1731890916729 |
| Square root | 109.585583 |
| Digit sum / digital root | 12 / 3 |
| Collatz steps to 1 | 81 |
| Scientific notation | 1.2009 × |
12009 in other forms
| Form | Value |
|---|---|
| In words | twelve thousand and nine |
| Binary (base 2) | 10111011101001 |
| Octal (base 8) | 27351 |
| Hexadecimal (base 16) | 2EE9 |
| Base 3 | 121110210 |
| As time | 12009 seconds = 3 h 20 min 9 s |
Is 12009 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 (12009 ÷ 3 = 4003) | 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 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 3) | 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 9) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 12009 a prime number?
No. 12009 = 3 × 4003, so it is divisible by 3.
What are the factors of 12009?
1, 3, 4003, 12009.
What is 12009 in binary?
10111011101001 (hexadecimal 2EE9, octal 27351).
What is the square root of 12009?
About 109.5856.
Is 12009 divisible by 3?
Yes. Its digits add up to 12, a multiple of 3.
What is special about the number 12009?
12009 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 3 × 4003, the product of two primes.