109

Number
$109$ (one hundred and nine) is:


 * The $29$rd prime number


 * The $8$th of $11$ primes of the form $2 x^2 + 11$:
 * $2 \times 7^2 + 11 = 109$


 * The $5$th prime number after $53, 71, 103, 107$ which cannot be expressed as the difference between a power of $2$ and a power of $3$.