U+2147 "ⅇ" Double-Struck Italic Small E Unicode Character

U+2147 "ⅇ" Double-Struck Italic Small E is a typographic symbol that represents the mathematical constant known as Euler's number, approximately equal to 2.71828, which is the base of the natural logarithm. This character belongs to the Letterlike Symbols block and is designed in a double-struck italic style to distinguish it from a regular lowercase letter "e" used in text. Its primary use is in scientific and mathematical notation, where it provides a clear and unambiguous way to denote this fundamental constant in formulas and equations. The double-struck or "blackboard bold" appearance is a common convention in mathematics to indicate specific sets or constants, ensuring the symbol stands out visually from ordinary variables.