Unexpected Behavior in Bash Script for Solaris 10

I am writing a shell script for Solaris 10, to allow for information gathering on our users, such as when their passwords are getting close to expiring. I am having trouble getting Bash to compute the integer math, which I know it is capable of. The error that I keep getting is :user_expire.sh: line 45: 15251: command not found

Which corresponds to the value that is stored in c_epoch variable.

Any Suggestions are appreciated. Please see my code so far below.
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#! /bin/bash

# This script takes the passwd file and determines the number of days until a
# user's account expires