37

This number is a prime.

37 is the initial prime which is not a factor of the order of the Monster Group having cardinality 808017424794512875886459904961710757005754368000000000=2^46*3^20*5^9*7^6*11^2*13^3*17*19*23*29*31*41*47*59*61. This finite sporadic simple group has generated much interest and constitutes a group of symmetries on 196883 dimensions. This group was discovered in 1982 by Robert Griess. [Schiffman]