What is the address class of IP address 133.66.155.189?

The IP address 133.66.155.189 falls under Class B. Class B addresses range from 128.0.0.0 to 191.255.255.255, and they are used for medium to large networks. The first octet, 133, indicates that it belongs to this class. In Class B, the first two octets are used for the network address, while the last two are used for host addresses.