0555

0555 is a numeric string that appears as the number 555 with a leading zero. In data formats and programming, a leading zero often signals octal notation or padding, while in user interfaces it may simply be part of a code or identifier.

In mathematics, ignoring the leading zero, 555 is a composite number with prime factorization 3 × 5 × 37. It is divisible by 15, making it a Harshad number in base 10. It is also a palindromic number when written as 555.

In computing and data encoding, 0555 is commonly seen as an octal literal. The octal value 0555 converts to decimal 365. As a Unix-like file permission mask, 0555 denotes the permission set -r-xr-xr-x, where the owner, group, and others all have read and execute permissions but not write.

Other uses include the year 555 CE, a datum in historical chronology, and the Roman numeral representation of 555, which is DLV. In culture and media, the sequence 555 is widely recognized as a fictitious telephone-number prefix in North American fiction, though 0555 as a six-digit string is less commonly used for phones and more likely to appear as a model number or internal code in catalogs and databases.