89

Number
$89$ (eighty-nine) is:


 * The $24$th prime number


 * The $10$th Sophie Germain prime after $2, 3, 5, 11, 23, 29, 41, 53, 83$:
 * $2 \times 89 + 1 = 179$, which is prime.


 * The $11$th Fibonacci number, after $1, 1, 2, 3, 5, 8, 13, 21, 34, 55$:
 * $89 = 34 + 55$


 * The $6$th of the sequence of $n$ such that $p_n \# - 1$, where $p_n \#$ denotes primorial of $n$, is prime:
 * $3, 5, 11, 13, 41, 89$