821

Number
$821$ (eight hundred and twenty-one) is:


 * The $142$nd prime number.


 * The larger of the $14$th pair of primes whose prime gap is $10$:
 * $821 - 811 = 10$


 * The $1$st of the $32$nd pair of twin primes:
 * $823 - 821 = 2$


 * The $50$th long period prime after $7$, $17$, $19$, $23$, $29$, $\ldots$, $701$, $709$, $727$, $743$, $811$

Also see