I just read an article on the JAL123 crash in 1983. Still the most single deadliest airplane crash to date. It was a 747SP-46 and could carry over 550 people according to the article.
I don't believe it was a 747SP but a 747SR. The SP
was a 747 shrink that increased range to pionner some city pairs we take for granted today. The SR
was a full 747 with reduced range, MTOW, passenger amenities, and gallies to accomodate as many passengers as possible.. thus making it a short/medium-haul aircraft. It was replaced by the 747-400D (Domestic) that was and is popular with ANA and JAL. To fit this many people, it is basically an all-economy configuration with no business and very few first-class seats.
Only these versions (747SR and 744D) were designed to transport this many people.