Numeric#to_utf8 -> turns a number into the UTF-8 string of its codepoint.

to_utf8.rb

# Defines a method
module CoreExtensions
  module CodepointToUTF8
    # Returns string of the number interpreted as a Unicode code point.
    def to_utf8
      # http://ruby-doc.org/core-2.2.2/Array.html#pack-method
      [self.truncate].pack("U")
    end

    # Installs the Monkey-Patch on Numeric.
    def self.install
      return if Numeric.method_defined? :to_utf8
      Numeric.include CoreExtensions::CodepointToUTF8
    end
  end
end