memberCount property
memberCount Number of members in the supergroup or channel; 0 if unknown. Currently, it is guaranteed to be known only if the supergroup or channel was received through getChatSimilarChats, getChatsToPostStories, getCreatedPublicChats, getGroupsInCommon, getInactiveSupergroupChats, getRecommendedChats, getSuitableDiscussionChats, getUserPrivacySettingRules, getVideoChatAvailableParticipants, searchPublicChats, or in chatFolderInviteLinkInfo.missing_chat_ids, or in userFullInfo.personal_chat_id, or for chats with messages or stories from publicForwards and foundStories
Implementation
final int memberCount;