The number 4009
4009 is a composite number with 4 divisors. Its prime factorisation is 19 × 211. Divisors (4): 1, 19, 211, 4009.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 4009: a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 19 × 211, the product of two primes.
- 2
4009 is composite. Its prime factorisation is
- 3
The divisors add up to 4240; without 4009 itself that is 231, so 4009 is deficient (231 is less than 4009). Euler's totient φ(4009) = 3780 numbers up to 4009 share no factor with it.
- 4
The digits of 4009 add up to 13, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 157 steps to reach 1.
LaTeX source of the formulas on this page
\[ 4009 = 19 \times 211 \]
4009 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 4240 |
| Euler totient φ(n) | 3780 |
| Square | 16072081 |
| Cube | 64432972729 |
| Square root | 63.316664 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 157 |
| Scientific notation | 4.009 × |
4009 in other forms
| Form | Value |
|---|---|
| In words | four thousand and nine |
| Binary (base 2) | 111110101001 |
| Octal (base 8) | 7651 |
| Hexadecimal (base 16) | FA9 |
| Base 3 | 12111111 |
| As time | 4009 seconds = 1 h 6 min 49 s |
Is 4009 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 1) | 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 1) | A number is divisible by 6 if it is divisible by both 2 and 3. |
| 7 | No (remainder 5) | 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 4) | 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 5) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 4009 a prime number?
No. 4009 = 19 × 211, so it is divisible by 19.
What are the factors of 4009?
1, 19, 211, 4009.
What is 4009 in binary?
111110101001 (hexadecimal FA9, octal 7651).
What is the square root of 4009?
About 63.3167.
Is 4009 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 4009?
4009 is a happy number: repeatedly adding the squares of its digits reaches 1; a semiprime: 19 × 211, the product of two primes.