The number 8409
8409 is a composite number with 4 divisors. Its prime factorisation is 3 × 2803. Divisors (4): 1, 3, 2803, 8409.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 8409: a semiprime: 3 × 2803, the product of two primes.
- 2
8409 is composite. Its prime factorisation is
- 3
The divisors add up to 11216; without 8409 itself that is 2807, so 8409 is deficient (2807 is less than 8409). Euler's totient φ(8409) = 5604 numbers up to 8409 share no factor with it.
- 4
The digits of 8409 add up to 21, and repeating that until one digit is left gives the digital root 3. The Collatz sequence (halve if even, else 3n+1) takes 65 steps to reach 1.
LaTeX source of the formulas on this page
\[ 8409 = 3 \times 2803 \]
8409 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 11216 |
| Euler totient φ(n) | 5604 |
| Square | 70711281 |
| Cube | 594611161929 |
| Square root | 91.700600 |
| Digit sum / digital root | 21 / 3 |
| Collatz steps to 1 | 65 |
| Scientific notation | 8.409 × |
8409 in other forms
| Form | Value |
|---|---|
| In words | eight thousand four hundred and nine |
| Binary (base 2) | 10000011011001 |
| Octal (base 8) | 20331 |
| Hexadecimal (base 16) | 20D9 |
| Base 3 | 102112110 |
| As time | 8409 seconds = 2 h 20 min 9 s |
Is 8409 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 (8409 ÷ 3 = 2803) | 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 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 5) | 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 8409 a prime number?
No. 8409 = 3 × 2803, so it is divisible by 3.
What are the factors of 8409?
1, 3, 2803, 8409.
What is 8409 in binary?
10000011011001 (hexadecimal 20D9, octal 20331).
What is the square root of 8409?
About 91.7006.
Is 8409 divisible by 3?
Yes. Its digits add up to 21, a multiple of 3.
What is special about the number 8409?
8409 is a semiprime: 3 × 2803, the product of two primes.