Lookup of 23.21.16.121
IP address: 23.21.16.121
Address type: IPv4
Host or reverse DNS (rDNS): ec2-23-21-16-121.compute-1.amazonaws.com
Country: 
United States
23.21.16.121 does NOT belong to a private IP address block.
23.21.16.121 does NOT belong to a reserved IP address block.