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 smaller of the $32$nd pair of twin primes:
 * $823 - 821 = 2$


 * The $38$th minimal prime base $10$ after $11$, $13$, $17$, $19$, $23$, $29$, $31$, $37$, $41$, $43$, $47$, $53$, $59$, $61$, $67$, $71$, $73$, $79$, $83$, $89$, $97$, $227$, $251$, $257$, $277$, $281$, $349$, $409$, $449$, $499$, $521$, $557$, $577$, $587$, $727$, $757$, $787$


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

Also see