The number 13531
13531 is a palindrome: it reads 13531 backwards too. Its prime factorisation is 7 × 1933. Divisors (4): 1, 7, 1933, 13531.
Pick any whole number from 1 to 100,000.
How to work it out
- 1
What is special about 13531: a palindrome: it reads 13531 backwards too; a semiprime: 7 × 1933, the product of two primes.
- 2
13531 is composite. Its prime factorisation is
- 3
The divisors add up to 15472; without 13531 itself that is 1941, so 13531 is deficient (1941 is less than 13531). Euler's totient φ(13531) = 11592 numbers up to 13531 share no factor with it.
- 4
The digits of 13531 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
\[ 13531 = 7 \times 1933 \]
13531 at a glance
| Property | Value |
|---|---|
| Type | composite |
| Number of divisors | 4 |
| Sum of divisors | 15472 |
| Euler totient φ(n) | 11592 |
| Square | 183087961 |
| Cube | 2477363200291 |
| Square root | 116.322827 |
| Digit sum / digital root | 13 / 4 |
| Collatz steps to 1 | 138 |
| Scientific notation | 1.3531 × |
13531 in other forms
| Form | Value |
|---|---|
| In words | thirteen thousand five hundred and thirty-one |
| Binary (base 2) | 11010011011011 |
| Octal (base 8) | 32333 |
| Hexadecimal (base 16) | 34DB |
| Base 3 | 200120011 |
| As time | 13531 seconds = 3 h 45 min 31 s |
Is 13531 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 3) | A number is divisible by 4 if the last two digits make a multiple of 4. |
| 5 | No (remainder 1) | 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 (13531 ÷ 7 = 1933) | 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 3) | 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 1) | A number is divisible by 10 if the last digit is 0. |
| 11 | No (remainder 1) | A number is divisible by 11 if the alternating sum of the digits is a multiple of 11. |
| 12 | No (remainder 7) | A number is divisible by 12 if it is divisible by both 3 and 4. |
Questions
Is 13531 a prime number?
No. 13531 = 7 × 1933, so it is divisible by 7.
What are the factors of 13531?
1, 7, 1933, 13531.
What is 13531 in binary?
11010011011011 (hexadecimal 34DB, octal 32333).
What is the square root of 13531?
About 116.3228.
Is 13531 divisible by 3?
No. Its digits add up to 13, which is not a multiple of 3.
What is special about the number 13531?
13531 is a palindrome: it reads 13531 backwards too; a semiprime: 7 × 1933, the product of two primes.