0020

0020 is a four-digit string that commonly represents the natural number 20 with two leading zeros. In pure mathematics, leading zeros do not change the value, so 0020 and 20 are identical as numbers.

The number 20 itself has several basic properties. It is even and composite, with divisors 1, 2, 4, 5, 10, and 20. Its prime factorization is 2^2 × 5. In other common bases, 20 is represented differently: in binary it is 10100, and in Roman numerals it is XX.

In computing and data formatting, leading zeros are often used to fix the width of numeric fields. A four-digit field may store 0001 through 9999, for consistent alignment, lexical ordering, or import/export compatibility. In some programming contexts, a leading zero can indicate octal notation; for example, in languages that interpret a leading zero as octal, 0020 would be interpreted as octal 20, which equals decimal 16. Many modern languages require explicit base indicators to avoid such ambiguity.

Calendrical usage can also appear with the string 0020, where it may denote the year AD 20 (20 CE) in systems that write years with four digits. In astronomical year numbering, the same year can align with corresponding conventions, though some systems differ for historical years around 1 CE and earlier.

In practice, 0020 is most often seen as a padded identifier or code in databases, inventory, or file naming, where fixed-width formatting is important. It serves as a simple example of how leading zeros affect representation without altering the underlying value.