997

Number
$997$ (nine hundred and ninety-seven) is:


 * The $168$th prime number


 * The $19$th obstinate number after $1$, $127$, $149$, $251$, $331$, $337$, $373$, $509$, $599$, $701$, $757$, $757$, $809$, $877$, $905$, $907$, $959$, $977$


 * The $23$rd of $29$ primes of the form $2 x^2 + 29$:
 * $2 \times 22^2 + 29 = 997$