71,850,239

Number
$71 \, 850 \, 239$ (seventy-one million, eight hundred and fifty thousand, two hundred and thirty-nine) is:


 * The $4 \, 220 \, 407$rd prime number


 * The $7$th and last term of the smallest Cunningham chain of length $7$:
 * $1 \, 122 \, 659$, $2 \, 245 \, 319$, $4 \, 490 \, 639$, $8 \, 981 \, 279$, $17 \, 962 \, 559$, $35 \, 925 \, 119$, $71 \, 850 \, 239$