Displaying the number in the name is one of the properties of the figure. By default, it is set to on if you are not using GUIDE .
In any case, to remove it, use
set(gcf,'NumberTitle','off');
It is best to use the handle you received from calling the figure function:
hFig = figure('Name','window 1','Visible','Off'); set(hFig,'NumberTitle','off');
Furthermore, (as @GuntherStruyf mentioned), this can be done in a call to the figure function itself:
hFig = figure('Name','window 1','Visible','Off','NumberTitle','off');
Andrey Rubshtein Jun 07 2018-12-12T00: 00Z
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