The first number is the kill’s base fame, the same one the summary shows. The second adds the zone, difficulty and Premium set in the picker above the loot table. Zones have their own fame multiplier, separate from the loot one. The global 0.9 factor on loot does not apply to fame. Personal fame buffs are not included. They multiply on top.
Everyone within 50 m of the kill shares the fame. First the party’s total is multiplied by 1.1 for two players, 1.17 for three, 1.33 for four and 1.4 for five or more. Then it is split, so each player gets 55% of solo fame in a party of two, 39% in three, 33% in four and 28% in five. The multiplier stops growing at five. A sixth player adds nothing to the total but still takes a share.