There are other segment types that are named for their file and block numbers - namely the bootstrap (cache) segment and temporary segments. So you may want to check X$KTTVS or DBA_SEGMENTS.SEGMENT_TYPE to make sure that you really are looking at deferred rollback segments. If so, just bringing all the datafiles for the corresponding tablespace back online should allow the saved undo to be applied and thereafter Oracle will drop these segments automatically.

How to get rid of deferred rollback segments in system tablespace? They do not have any names for this segments just the numbers like 111.23, etc.