How do I count the trailing zeros in integer?

May be you can try doing this. This may be easier than counting each trailing '0's

def trailing_zeros(longint):
    manipulandum = str(longint)
    return len(manipulandum)-len(manipulandum.rstrip('0'))

For strings, it is probably the easiest to use rstrip():

In [2]: s = '23989800000'

In [3]: len(s) - len(s.rstrip('0'))
Out[3]: 5