December 12 is the 346th day of the year. There are 19 days left.

Today's number is 12

July 18 is the 199th day of the year. There are 166 days left.

18 is a multiple of 9, 3, and 6, leading to suspicions that it will generate unending fractions (more later)

18 is the sum of 3 of its divisors, 3, 6, and 9
18 is argon, a noble gas
18 is the group containing noble (inert) gases in the periodic table