Thats unicode code, byte value in unicode encoding that represents that character, you don’t need that code you can copy paste symbol anywhere where unicode is supported (not in C++ thru, you need to use this code in strings \uE87C). Unreal support unicode, you just need set up font that support specific character (again that code is bytes that represent character)
Now about your code, that code is in private range, in the past emojis was not officially supported in unicode, there for mobile phone OS developers used so called private use range (E000-EFFF) dedicated for your own symbols. So you should not use that code anymore as emoji been recently (Unicode version 6.0) added officially to unicode tables, you can check there codes here, use them instead (also in web!):