Have you ever thought what is the significance of the first letter of the passport number? Jump into the loop to know about this...

It does not denote anything. It is just an alpha sequence to go with the numeric sequence.

It is a series of passports. It is usually assigned in increasing order. Eg. For two people who apply on the same day, chances are they will have at least 3–4 common digits on the passport in an 8-digit series.