U+1D7E1 "𝟡" Mathematical Double-Struck Digit Nine Unicode Character
Unicode Version 17.0
𝟡
U+1D7E1 "𝟡" Mathematical Double-Struck Digit Nine is a stylized numeral from the Mathematical Alphanumeric Symbols block, designed with the distinctive double struck or blackboard bold style often used in mathematical notation. This digit nine is typically employed in typesetting for set theory, number theory, or other mathematical contexts where a special, emphasized numeral is needed to distinguish it from standard digits, such as representing the set of integers or as a symbolic digit in abstract algebraic expressions. It is rendered in Unicode as part of a complete set of double struck digits from zero to nine, allowing for consistent formatting in digital text and mathematical documents.
General Properties
| Code Point | U+1D7E1 |
| Version Added | 3.1 |
| Name | Mathematical Double-Struck Digit Nine |
| Block | Mathematical Alphanumeric Symbols |
| General Category | Decimal Number |
| Canonical Combining Class | Not Reordered |
| Bidirectional Class | European Number |
| Decomposition Type | Font |
| Decomposition Mapping | "9" U+0039 Digit Nine |
Encodings
| HTML Decimal Encoding | 𝟡 |
| HTML Hex Encoding | 𝟡 |
| UTF-8 Encoding | 0xF0 0x9D 0x9F 0xA1 |
| UTF-16 Encoding | 0xD835 0xDFE1 |
| UTF-32 Encoding | 0x0001D7E1 |
| C/C++/Java Escape | \ud835\udfe1 |
Unicode Properties
| NFC Quick Check | Yes |
| NFD Quick Check | Yes |
| Numeric Type | Decimal |
| Numeric Value | 9 |
| Line Break | Numeric |
| Changes When NFKC Casefolded | Yes |
| NFKC Casefold | "9" U+0039 Digit Nine |
| NFKC Simple Casefold | "9" U+0039 Digit Nine |
| Script | Common |
| Script Extensions | Common |
| Indic Syllabic Category | Other |
| ID Continue | Yes |
| XID Continue | Yes |
| Math | Yes |
| Other Math | Yes |
| Vertical Orientation | Rotated |
| Grapheme Base | Yes |
| Grapheme Cluster Break | Other |
| Word Break | Numeric |
| Sentence Break | Numeric |