March 18 is the 81st day of the Gregorian Calendar year
Boomtime, Discord 4, 3185 YOLD (discordian)
And let us not forget 13.0.6.5.18 by the Mayan Long Count

Happy commemoration of Sen no Rikyū

Today's number is 28

28 is 4 x 7 (more later)

28 is the sum of the first 7 natural numbers. 1+2+3+4+5+6+7 = 28

28 is also the sum of the first 5 non-primes 1+4+6+8+9 = 28