mysql match against boolean mode
You may need to try some wildcard stuff

MATCH (field) AGAINST ('+85604*' IN BOOLEAN MODE)
MATCH (field) AGAINST ('+8560*' IN BOOLEAN MODE)


The MySQL Documentation says on '*':


  *
  
  The asterisk serves as the truncation (or wildcard) operator. Unlike
  the other operators, it is appended to the word to be affected. Words
  match if they begin with the word preceding the * operator.
  
  If a word is specified with the truncation operator, it is not
  stripped from a boolean query, even if it is too short or a stopword.
  Whether a word is too short is determined from the
  innodb_ft_min_token_size setting for InnoDB tables, or ft_min_word_len
  for MyISAM tables. The wildcarded word is considered as a prefix that
  must be present at the start of one or more words. If the minimum word
  length is 4, a search for '+word +the*' could return fewer rows than a
  search for '+word +the', because the second query ignores the
  too-short search term the.


Here is an example from the Documentation:


  'apple*'
  
  Find rows that contain words such as “apple”, “apples”, “applesauce”,
  or “applet”.


For more information, see MySQL Documentation on Fine Tuning Your Searches