Conversion of a column from Integer format type to 'timestamp with time zone'

[Raj kumar <rajkumar820999@xxxxxxxxx>]

Hi, there is a column 'created' in the 'customers' table which is actually supposed to be a 'timestamp with time zone' column but stored in this Integer format. How do I typecast this to 'timestamp with time zone' format?

select created from customers limit 3;
    created
---------------
 1521521848681
 1508995056368
 1521559994299
(3 rows)

Thanks,

Raj Kumar Narendiran.