34 (number)
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34 is a natural number that lies between 33 and 35. It is an even number divisible by two, and a composite number that is not prime.
Its complete divisors are 1, 2, 17, and 34. When broken down into prime factors, it equals 2 × 17. For this reason it belongs to the semiprime numbers, which are products of exactly two prime numbers.
Mathematical properties
The sum of its proper divisors (1 + 2 + 17) is 20, which is less than 34; therefore it is a deficient number. It is also a number in the Fibonacci sequence, whose terms are 1, 1, 2, 3, 5, 8, 13, 21, 34, where each number is the sum of the two preceding ones.
34 is notable in the study of magic squares: a 4×4 magic square containing the numbers 1 through 16 has a sum of 34 in each row, column, and diagonal. A famous example appears in Albrecht Dürer's engraving "Melancholia I".
Notation and number systems
In Roman numerals it is written XXXIV. In binary it is 100010, in octal it is 42, and in hexadecimal it is 22.
Other uses
34 serves as a reference number in various systems, such as road numbers, telephone country codes (for example, Spain's international dialing code is +34), and sports team numbers. It is also the atomic number of selenium on the periodic table.