Using psql's \prompt command

I want to use the \prompt command to get user input for a query. My script
fails:

-- Display person_nbr, lname, fname, direct_phone, email from people, contact history from contacts.

-- prompt for person_nbr before selecting rows:
\prompt 'Enter person_nbr: ' store

select p.person_nbr, p.lname, p.fname, p.direct_phone, p.email, c.contact_date, c.contact_time, c.contact_type,
c.notes
from people as p natural inner join contacts as c
where person_nbr = store
order by c.contact_date, c.contact_time;

# \i person_view.sql
Enter person_nbr: 468
psql:person_view.sql:9: ERROR:  column "store" does not exist
LINE 3: where person_nbr = store
                            ^
What's the correct syntax for the \prompt?

TIA,

Rich