421

Number
$421$ (four hundred and twenty-one) is:


 * The $82$nd prime number


 * The smaller of the $7$th pair of primes whose prime gap is $10$:
 * $431 - 421 = 10$


 * The $15$th of $29$ primes of the form $2 x^2 + 29$:
 * $2 \times 14^2 + 29 = 421$


 * The $2$nd of the $22$nd pair of twin primes:
 * $421 - 419 = 2$