Dezessete

Dezessete is the Portuguese word for the integer 17. It is used in Portugal, Brazil, and other Portuguese-speaking communities to denote the number that comes after 16 and before 18.

Etymology: The term dezes sete derives from dez (ten) and sete (seven). Through phonetic assimilation, the compound forms dezessete.

Mathematics: 17 is a prime number, the seventh prime. It is also a Fermat prime, since 17 equals 2^(2^2) + 1. In number theory, 17 can be expressed as the sum of two squares: 1^2 + 4^2. In common numeral systems, it is written as XVII in Roman numerals; in binary as 10001; and in hexadecimal as 0x11 (or 11 in hex).

Language and culture: The ordinal form is décimo sétimo. In Portuguese, dezenasete is used for the cardinal form, while décimo séttimo denotes the position in a sequence. Culturally, the number 17 does not carry a widespread superstition in most Portuguese-speaking countries, though in various European cultures it is sometimes regarded as unlucky.

See also: 17 (number).