Akshouhini

An akshauhini , is described in the  Mahabharata as a battle formation consisting of 21,870 chariots (Sanskrit ratha); 21,870 elephants; 65,610 cavalry and 109,350 infantry as per the Mahabharata (Adi Parva 2.15-23). The ratio is 1 chariot : 1 elephant : 3 cavalry : 5 infantry soldiers. In each of these large number groups (65,610, etc.), the digits add up to 18.