4.4.0-98.121) is not available, but a newer one is (4.4.0-142.168). We redirected you there.
/usr/bin/clstr_reduce is in cd-hit 4.6.6-2.
This file is owned by root:root, with mode 0o777.
It is a symlink to /usr/bin/../lib/cd-hit/clstr_reduce.pl