Mathematical Monospace Digit One
HTML Entity Browser Test:

U+1D7F7 is the Unicode hex value of the character Mathematical Monospace Digit One, which is categorized as "decimal digit number" in the Unicode 6.0 character table.

In addition, U+1D7F7 is a composite character comprising of one or more other Unicode characters modified or combined.

Unicode Character Information
Unicode Hex U+1D7F7
General Category Decimal Digit Number [Code: Nd]
Canonical Combining Class 0
Bidirectional Category EN
Decomposition Mapping <font> 0031
Numeric Value 1
Mirrored N
Unicode Character Encodings
Mathematical Monospace Digit One HTML Entity &#120823; (decimal entity), &#x1D7F7; (hex entity)
Windows Key Code Alt 120823 or Alt +1D7F71
Programming Source Code Encodings Python hex: u"\u1D7F7", Hex for C++ and Java: "\u1D7F7"
UTF-8 Hexadecimal Encoding 0xF09D9FB7
1 To type a Unicode symbol in Windows, hold down the ALT key and enter the decimal or hexadecimal code provided using the numeric keypad. The decimal alt code (Alt 120823) will only work on computers with support for this Unicode character in the active code page. The hexadecimal alt code (Alt +1D7F7) will work for all Unicode characters provided Hex input from the numeric keypad is enabled.
* If the Mathematical Monospace Digit One character does not display correctly in your browser, you may not have a Unicode font on your system that supports this particular symbol.