Since There's always MTOWTDI (and I'm experimenting with look-ahead assertions):

#!/perl/bin/perl -w
use strict;
use Data::Dumper;
use List::Util qw/ max /;

my $s = "ASBSDEC 34 GADVVEEVEETTE 56 IOEOREAK GKJEOG EFEAF 1090 DAFFEE
+ 376";

# use a look-ahead assertion to split string into array of strings and
+ numbers
# the corresponding string occupies the index immediately preceding th
+e number
my @arr = split /(\D+)(?=\d+)/, $s;

# grep only for the numbers in the list, selecting the largest one 
print max(grep { /^\d+$/ } @arr), "\n";

__OUTPUT__
1090
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Update: Corrected typo diligently found by liverpole++