How do I gain citizenship after residency?

Investor visa holders may apply for Brazilian Citizenship after 4 years of official legal residency in Brazil for normal cases or 1­3 years in special cases. One year of official legal residency is considered at least 6 months plus one day of stay in the country out of each year, not necessarily as a continuous stay. As long as the foreigner has not stayed out of Brazil for more than 18 months during this 4 years period and has some elementary knowledge of the Portuguese language, they will be able to obtain citizenship.