85

Number
$85$ (eighty-five) is:


 * $5 \times 17$


 * The $27$th semiprime:
 * $85 = 5 \times 17$


 * The $3$rd positive integer after $50, 65$ which can be expressed as the sum of two square numbers in two or more different ways:
 * $85 = 9^2 + 2^2 = 7^2 + 6^2$


 * The $16$th positive integer $n$ after $5, 11, 17, 23, 29, 30, 36, 42, 48, 54, 60, 61, 67, 73, 79$ such that no factorial of an integer can end with $n$ zeroes.


 * The $7$th positive integer which cannot be expressed as the sum of a square and a prime:
 * $1, 10, 25, 34, 58, 64, 85, \ldots$


 * The $4$th non-square positive integer which cannot be expressed as the sum of a square and a prime:
 * $10, 34, 58, 85, \ldots$