The number 13405
13405 is a composite number with 8 divisors. Its prime factorisation is 5 × 7 × 383. Divisors (8): 1, 5, 7, 35, 383, 1915, 2681, 13405.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
13405 has no famous special property in the usual lists (prime, square, cube, triangular, Fibonacci, palindrome, perfect), but it is still a composite number.
- 2
13405 is composite. Its prime factorisation is
- 3
The divisors add up to 18432; without 13405 itself that is 5027, so 13405 is deficient (5027 is less than 13405). Euler's totient φ(13405) = 9168 numbers up to 13405 share no factor with it.
- 4
The digits of 13405 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 138 steps to reach 1.
LaTeX source of the formulas on this page
\[ 13405 = 5 \times 7 \times 383 \]
13405 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 8 |
| Sum of divisors | 18432 |
| Euler totient φ(n) | 9168 |
| Square | 179694025 |
| Cube | 2408798405125 |
| Square root | 115.779964 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 138 |
| Scientific notation | 1.3405 × |
13405 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand four hundred and five |
| Binary (base 2) | 11010001011101 |
| Octal (base 8) | 32135 |
| Hexadecimal (base 16) | 345D |
| Base 3 | 200101111 |
| As time | 13405 seconds = 3 h 43 min 25 s |
Is 13405 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 | Yes (13405 ÷ 5 = 2681) | 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 (13405 ÷ 7 = 1915) | 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 5) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 7) | 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 13405 a prime number?
No. 13405 = 5 × 7 × 383, so it is divisible by 5.
What are the factors of 13405?
1, 5, 7, 35, 383, 1915, 2681, 13405.
What is 13405 in binary?
11010001011101 (hexadecimal 345D, octal 32135).
What is the square root of 13405?
About 115.7800.
Is 13405 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 13405?
It is a composite number with 8 divisors.