1

← 0 1 2 →
−1 0 1 2 3 4 5 6 7 8 9
Cardinalone
Ordinal1st
(first)
Numeral systemunary
Factorization
Divisors1
Greek numeralΑ´
Roman numeralI, i
Greek prefixmono-/haplo-
Latin prefixuni-
Binary12
Ternary13
Senary16
Octal18
Duodecimal112
Hexadecimal116
Greek numeralα'
Arabic, Kurdish, Persian, Sindhi, Urdu١
Assamese & Bengali
Chinese numeral一/弌/壹
Devanāgarī
Ge'ez
GeorgianႠ/ⴀ/ა(Ani)
Hebrewא
Japanese numeral一/壱
Kannada
Khmer
ArmenianԱ
Malayalam
Meitei
Thai
Tamil
Telugu
Babylonian numeral𒐕
Egyptian hieroglyph, Aegean numeral, Chinese counting rod𓏤
Mayan numeral
Morse code. _ _ _ _

1 (one, unit, unity) is a number, numeral, and glyph. It is the first and smallest positive integer of the infinite sequence of natural numbers. This fundamental property has led to its unique uses in other fields, ranging from science to sports, where it commonly denotes the first, leading, or top thing in a group. 1 is the unit of counting or measurement, a determiner for singular nouns, and a gender-neutral pronoun. Historically, the representation of 1 evolved from ancient Sumerian and Babylonian symbols to the modern Arabic numeral.

In mathematics, 1 is the multiplicative identity, meaning that any number multiplied by 1 equals the same number. 1 is by convention not considered a prime number. In digital technology, 1 represents the "on" state in binary code, the foundation of computing. Philosophically, 1 symbolizes the ultimate reality or source of existence in various traditions.