Reverse DNS Lookup
This tool will provide you the hostname (ie www.yahoo.com) of the IP address that you enter below.
Results:
Lookup on IPv4 Address: 216.58.212.145
Hostname: ams15s21-in-f145.1e100.net
Hostname: ams15s21-in-f17.1e100.net
Hostname: fra16s46-in-f17.1e100.net