281

Number
$281$ (two hundred and eighty-one) is:


 * The $60$th prime number


 * The $1$st of the $19$th pair of twin primes, with $283$


 * The $19$th Sophie Germain prime after $2, 3, 5, 11, 23, 29, 41, 53, 83, 89, 113, 131, 173, 179, 191, 233, 239, 251$:
 * $2 \times 281 + 1 = 563$, which is prime.


 * The $1$st of a triplet of consecutive integers which have the property that if their digits are multiplied, and the process repeated on the result until only $1$ digit remains, that final digit is the same for all three:
 * $2 \times 8 \times 1 = 16; 1 \times 6 = 6$