A symmetric number is a number that remains the same when its digits are reversed. For example, the number 121 is symmetric because reading it backward also gives 121. Symmetric numbers are often referred to as palindromic numbers and can be found in various numeral systems. These numbers can be of any length, such as 7, 44, or 12321. Symmetric numbers are interesting in mathematics and are often studied in number theory. They can also appear in everyday contexts, such as dates, like 02/02/2020, which is symmetric when written in a specific format.