By default, pgAdmin uses port number 5432 to connect to a PostgreSQL database. However, it is possible that the port number may have been changed during the installation or configuration process. To check the default port number, you can refer to the PostgreSQL configuration file 'postgresql.conf' on your server.
Alternatively, you can also use the following code snippet in Python to retrieve the default port number programmatically:
import psycopg2
# Establish a connection with the PostgreSQL server
conn = psycopg2.connect(database="your_database_name", user="your_username", password="your_password", host="your_host", port="your_port")
# Print the default port number
print(conn.get_dsn_parameters()["port"])