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