Who stores the blockchain?

Can you please clarify who exactly stores the blockchain? Is it a centralized entity, such as a government or corporation, or is it a decentralized network of individuals? Are there specific hardware requirements for storing the blockchain, or can it be stored on any type of device? Also, is the blockchain stored in its entirety by every node in the network, or is it divided among nodes in some way? Lastly, what measures are in place to ensure the security and integrity of the blockchain?