Which of the following numbers is different from the rest?
$$\text{13, 17, 23, 27, 29}$$

Let's analyze the mathematical properties of the numbers in the given list:
* $13$ is a prime number (divisible only by $1$ and itself).
* $17$ is a prime number.
* $23$ is a prime number.
* $29$ is a prime number.
* $27$ is a composite number because it has factors other than $1$ and itself ($1,3,9,27$).

Therefore, $27$ is the odd one out.