1409

Number
$1409$ (one thousand, four hundred and nine) is:


 * The $223$rd prime number


 * The larger of the $24$th pair of primes whose prime gap is $10$:
 * $1409 - 1399 = 10$


 * The $46$th Sophie Germain prime after $2$, $3$, $5$, $11$, $23$, $29$, $41$, $\ldots$, $761$, $809$, $911$, $953$, $1013$, $1019$, $1031$, $1049$, $1103$, $1223$, $1229$, $1289$:
 * $2 \times 1409 + 1 = 2819$, which is prime.