Mathematical Bold Capital Theta Symbol
HTML Entity Browser Test:

U+1D6B9 is the Unicode hex value of the character Mathematical Bold Capital Theta Symbol, which is categorized as "uppercase letter" in the Unicode 6.0 character table.

In addition, U+1D6B9 is a composite character comprising of one or more other Unicode characters modified or combined.

Unicode Character Information
Unicode Hex U+1D6B9
General Category Uppercase Letter [Code: Lu]
Canonical Combining Class 0
Bidirectional Category L
Decomposition Mapping <font> 03F4
Mirrored N
Unicode Character Encodings
Mathematical Bold Capital Theta Symbol HTML Entity &#120505; (decimal entity), &#x1D6B9; (hex entity)
Windows Key Code Alt 120505 or Alt +1D6B91
Programming Source Code Encodings Python hex: u"\u1D6B9", Hex for C++ and Java: "\u1D6B9"
UTF-8 Hexadecimal Encoding 0xF09D9AB9
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 120505) will only work on computers with support for this Unicode character in the active code page. The hexadecimal alt code (Alt +1D6B9) will work for all Unicode characters provided Hex input from the numeric keypad is enabled.
* If the Mathematical Bold Capital Theta Symbol character does not display correctly in your browser, you may not have a Unicode font on your system that supports this particular symbol.