The number 13813
13813 is a composite number with 4 divisors. Its prime factorisation is 19 × 727. Divisors (4): 1, 19, 727, 13813.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 13813: a semiprime: 19 × 727, the product of two primes.
- 2
13813 is composite. Its prime factorisation is
- 3
The divisors add up to 14560; without 13813 itself that is 747, so 13813 is deficient (747 is less than 13813). Euler's totient φ(13813) = 13068 numbers up to 13813 share no factor with it.
- 4
The digits of 13813 add up to 16, and repeating that until one digit is left gives the digital root 7. The Collatz sequence (halve if even, else 3n+1) takes 45 steps to reach 1.
LaTeX source of the formulas on this page
\[ 13813 = 19 \times 727 \]
13813 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 14560 |
| Euler totient φ(n) | 13068 |
| Square | 190798969 |
| Cube | 2635506158797 |
| Square root | 117.528720 |
| Digit sum / digital root | 16 / 7 |
| Collatz steps to 1 | 45 |
| Scientific notation | 1.3813 × |
13813 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand eight hundred and thirteen |
| Binary (base 2) | 11010111110101 |
| Octal (base 8) | 32765 |
| Hexadecimal (base 16) | 35F5 |
| Base 3 | 200221121 |
| As time | 13813 seconds = 3 h 50 min 13 s |
Is 13813 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 3) | 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 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 5) | A number is divisible by 8 if the last three digits make a multiple of 8. |
| 9 | No (remainder 7) | A number is divisible by 9 if the digits add up to a multiple of 9. |
| 10 | No (remainder 3) | 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 1) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 13813 a prime number?
No. 13813 = 19 × 727, so it is divisible by 19.
What are the factors of 13813?
1, 19, 727, 13813.
What is 13813 in binary?
11010111110101 (hexadecimal 35F5, octal 32765).
What is the square root of 13813?
About 117.5287.
Is 13813 divisible by 3?
No. Its digits add up to 16, which is not a multiple of 3.
What is special about the number 13813?
13813 is a semiprime: 19 × 727, the product of two primes.