0142857

0142857 is a seven-digit decimal string that, when interpreted numerically, equals 142857. The leading zero means that in contexts where the value is treated strictly as a number, it is usually considered the same as 142857; however, as a textual code it can function as a fixed-length identifier or catalog number where the leading zero matters for sorting or formatting.

In mathematics, 142857 is notable as the repeating block of the decimal expansion of 1/7. It is often described as a cyclic number because certain multiples of 142857 produce rotations of its digits (for example, 2 × 142857 = 285714, 3 × 142857 = 428571, and so on). The version with a leading zero, 0142857, does not retain this rotational property when the digits are treated as a 7-digit string with the zero fixed in front; the leading zero alters the pattern in simple arithmetic rotations.

Common uses for the exact string 0142857 are as a fixed-length identifier in databases, file naming schemes, inventory or asset tags, or other systems that require uniform digit counts for alignment and lexicographic sorting. Outside of such identifier contexts, the more familiar reference is the number 142857 and its mathematical significance in modular arithmetic and cyclic-digit properties.

See also: 142857, cyclic number, fixed-length formatting, leading zero.