U+2124 "ℤ" Double-Struck Capital Z Unicode Character

U+2124 "ℤ" Double-Struck Capital Z is a typographic symbol from the letterlike symbols block that represents the set of all integers in mathematical notation, deriving its distinctive double-struck or blackboard bold style from an old convention of using bold type for number sets. It is widely used in fields such as number theory, algebra, and discrete mathematics to denote the infinite set of whole numbers including negative numbers, zero, and positive numbers. The character is encoded separately from the standard Latin capital Z to serve a specific mathematical purpose and is distinct from the similar-looking but unrelated "Z" in the Mathematical Alphanumeric Symbols block.

General Properties

Code Point	U+2124
Version Added	1.1
Name	Double-Struck Capital Z
Unicode 1.0 Name	Double-Struck Z
Block	Letterlike Symbols
General Category	Uppercase Letter
Canonical Combining Class	Not Reordered
Bidirectional Class	Left To Right
Decomposition Type	Font
Decomposition Mapping	"Z" U+005A Latin Capital Letter Z

Encodings

HTML Decimal Encoding	ℤ
HTML Hex Encoding	ℤ
UTF-8 Encoding	0xE2 0x84 0xA4
UTF-16 Encoding	0x2124
UTF-32 Encoding	0x00002124
C/C++/Java Escape	\u2124

Unicode Properties

NFC Quick Check	Yes
NFD Quick Check	Yes
Numeric Type	None
Numeric Value	NaN
Line Break	Alphabetic
Uppercase	Yes
Cased	Yes
Changes When NFKC Casefolded	Yes
NFKC Casefold	"z" U+007A Latin Small Letter Z
NFKC Simple Casefold	"z" U+007A Latin Small Letter Z
Script	Common
Script Extensions	Common
Indic Syllabic Category	Other
ID Start	Yes
XID Start	Yes
ID Continue	Yes
XID Continue	Yes
Alphabetic	Yes
Math	Yes
Other Math	Yes
Vertical Orientation	Rotated
Grapheme Base	Yes
Grapheme Cluster Break	Other
Word Break	Alphabetic letter
Sentence Break	Upper