Since: cosmos-sdk 0.47
address is the account address string.
curl -L \ --url 'https://coreum.nownodes.io/cosmos/auth/v1beta1/account_info/{address}'
{ "info": { "address": "text", "pub_key": { "@type": "text", "ANY_ADDITIONAL_PROPERTY": "anything" }, "account_number": "text", "sequence": "text" } }