XCIII

XCIII is the Roman numeral representing the number 93. It is formed by combining XC (90) and III (3). In subtractive notation, XC denotes 100 minus 10, followed by the addition of 3, yielding 93.

In mathematics, 93 is a composite number with prime factorization 3 × 31. Its positive divisors are 1, 3, 31, and 93.

In science, 93 is the atomic number of neptunium, a radioactive actinide. Neptunium was first synthesized in 1940 by Edwin M. McMillan and Philip H. Abelson at the University of California, Berkeley, by irradiating uranium with neutrons. It is named after the planet Neptune and bears the chemical symbol Np.

As a numeral, XCIII appears in contexts where Roman numerals are used, such as outlines, legal documents, clock faces, or the designation of volumes and chapters. In everyday modern notation, Arabic numerals (93) are more common, but Roman numerals continue to appear in formal, historical, or stylistic uses.

See also Roman numerals; neptunium.