# 281

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## Number

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

The $60$th prime number

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:
$2 \times 8 \times 1 = 16$; $1 \times 6 = 6$

The smaller 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.