Interruption during a conversation is not perceived as rude and is fairly normal.
As with many other South American cultures, light touching is very common and is not perceived as inappropriate.
Brazilians prefer to be fashionably late, so if you are invited somewhere while in Brazil, show up about one hour after the time they tell you to arrive.

https://www.cia.gov/library/publications/the-world-factbook/geos/br.html (Majority of information)
ftp://ftp.ibge.gov.br/Estimativas_de_Populacao/Estimativas_2014/estimativa_dou_2014.pdf (City population)
Wolfram|Alpha (Currency exchange data)
Information accurate to best of ability as of 28 October 2016