IPdata API is the best way to get information about any IP address. They have a summary page which gives you overall info. I personally use Raw data section which has good info to find out any CIDR block related to a company.

Ipdata is a fantastic service which provides IP data like the location, time zone, currency, language, and other data related to an IP address. And on top of that IPdata's API is highly accurate and reliable, with real-time data updates and support for IPv4 and IPv6 addresses