What number is the British former secret agent known as in the TV series 'The Prisoner'?

The Prisoner is a 17-episode British television series first broadcast in Canada beginning on September 6, 1967 then in the United Kingdom on 29 September 1967 and in the USA on June 1, 1968. It stars and was co-created by Patrick McGoohan, and combines spy fiction with elements of science fiction, allegory and psychological drama.

The series follows a British former secret agent who is abducted and held prisoner in a mysterious coastal village resort, where his captors try to find out why he abruptly resigned from his job.

They do not use names, but have been assigned numbers which give no clue as to any person's status within the Village, whether as inmate or guard. Potential escapees therefore have no idea whom they can and cannot trust. The protagonist is assigned Number Six, but he repeatedly refuses the pretence of his new identity. Number Six is monitored heavily by Number Two, the Village administrator, who acts as an agent for an unseen "Number One". A variety of techniques are used by Number Two to try to extract information from Number Six, including hallucinogenic drug experiences, identity theft, mind control, dream manipulation, and various forms of social indoctrination and physical coercion. All of these are employed not only to find out why Number Six resigned as an agent, but also to elicit other purportedly dangerous information he gained as a spy.