The number 13909
13909 is a composite number with 4 divisors. Its prime factorisation is 7 × 1987. Divisors (4): 1, 7, 1987, 13909.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 13909: a semiprime: 7 × 1987, the product of two primes.
- 2
13909 is composite. Its prime factorisation is
- 3
The divisors add up to 15904; without 13909 itself that is 1995, so 13909 is deficient (1995 is less than 13909). Euler's totient φ(13909) = 11916 numbers up to 13909 share no factor with it.
- 4
The digits of 13909 add up to 22, and repeating that until one digit is left gives the digital root 4. The Collatz sequence (halve if even, else 3n+1) takes 32 steps to reach 1.
LaTeX source of the formulas on this page
\[ 13909 = 7 \times 1987 \]
13909 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 15904 |
| Euler totient φ(n) | 11916 |
| Square | 193460281 |
| Cube | 2690839048429 |
| Square root | 117.936424 |
| Digit sum / digital root | 22 / 4 |
| Collatz steps to 1 | 32 |
| Scientific notation | 1.3909 × |
13909 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand nine hundred and nine |
| Binary (base 2) | 11011001010101 |
| Octal (base 8) | 33125 |
| Hexadecimal (base 16) | 3655 |
| Base 3 | 201002011 |
| As time | 13909 seconds = 3 h 51 min 49 s |
Is 13909 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 | Yes (13909 ÷ 7 = 1987) | 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 5) | 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 13909 a prime number?
No. 13909 = 7 × 1987, so it is divisible by 7.
What are the factors of 13909?
1, 7, 1987, 13909.
What is 13909 in binary?
11011001010101 (hexadecimal 3655, octal 33125).
What is the square root of 13909?
About 117.9364.
Is 13909 divisible by 3?
No. Its digits add up to 22, which is not a multiple of 3.
What is special about the number 13909?
13909 is a semiprime: 7 × 1987, the product of two primes.