460 100。 The first six digits of the ID number in Haikou City, Hainan Province are 460 100246. These six digits represent the administrative division code of Haikou City, which is used to identify the domicile of the ID card holder. Specifically, the first 1 and 2 digits represent the codes of provinces, the third and fourth digits represent the codes of cities, and the fifth and sixth digits represent the codes of districts and counties.