2 (two) is a

number A number is a mathematical object used to count, measure, and label. The most basic examples are the natural numbers 1, 2, 3, 4, and so forth. Numbers can be represented in language with number words. More universally, individual numbers can ...

, numeral and digit. It is the

natural number In mathematics, the natural numbers are the numbers 0, 1, 2, 3, and so on, possibly excluding 0. Some start counting with 0, defining the natural numbers as the non-negative integers , while others start with 1, defining them as the positive in ...

following 1 and preceding 3. It is the smallest and the only even

prime number A prime number (or a prime) is a natural number greater than 1 that is not a Product (mathematics), product of two smaller natural numbers. A natural number greater than 1 that is not prime is called a composite number. For example, 5 is prime ...

. Because it forms the basis of a duality, it has

religious Religion is a range of social- cultural systems, including designated behaviors and practices, morals, beliefs, worldviews, texts, sanctified places, prophecies, ethics, or organizations, that generally relate humanity to supernatural ...

and spiritual significance in many

cultures Culture ( ) is a concept that encompasses the social behavior, institutions, and Social norm, norms found in human societies, as well as the knowledge, beliefs, arts, laws, Social norm, customs, capabilities, Attitude (psychology), attitudes ...

Mathematics

The number 2 is the second natural number after 1. Each natural number, including 2, is constructed by succession, that is, by adding 1 to the previous natural number. 2 is the smallest and the only even

, and the first Ramanujan prime. It is also the first superior highly composite number, and the first colossally abundant number. An integer is determined to be Parity (mathematics), even if it is Division (mathematics), divisible by two. When written in base 10, all Multiple (mathematics), multiples of 2 will end in 0, 2, 4, 6, or 8; more generally, in any even base, even numbers will end with an even digit. A digon is a polygon with two sides (or Edge (geometry), edges) and two Vertex (geometry), vertices. Two distinct point (geometry), points in a Plane (geometry), plane are always Necessity and sufficiency, sufficient to define a unique line (geometry), line in a nontrivial Euclidean space. A Set theory, set that is a field (mathematics), field has a minimum of two Element (mathematics), elements. Binary number, Binary is a number system with a radix, base of two, it is used extensively in Computer, computing.

As a word

''Two'' is most commonly a English determiners, determiner used with Grammatical number, plural countable nouns, as in ''two days'' or ''I'll take these two''. ''Two'' is a English nouns, noun when it refers to the number two as in ''two plus two is four.'' The word ''two'' is derived from the Old English words (Grammatical gender, feminine), (neuter), and (masculine, which survives today in the form wikt:twain, twain).

Evolution of the Arabic digit

The digit used in the modern Western world to represent the number 2 traces its roots back to the Indic Brahmic script, where "2" was written as two horizontal lines. The modern Chinese written language, Chinese and Japanese writing system, Japanese languages (and Korean Hanja) still use this method. The Gupta script rotated the two lines 45 degrees, making them diagonal. The top line was sometimes also shortened and had its bottom end curve towards the center of the bottom line. In the Devanagari, Nagari script, the top line was written more like a curve connecting to the bottom line. In the Arabic Ghubār numerals, Ghubar writing, the bottom line was completely vertical, and the digit looked like a dotless closing question mark. Restoring the bottom line to its original horizontal position, but keeping the top line as a curve that connects to the bottom line leads to our modern digit.

In science

* The first Magic number (physics), magic number - number of electrons in the innermost electron shell of an atom.

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