118

118 is the natural number that comes after 117 and before 119. It is an even composite number. Its prime factorization is 2 × 59, with 59 being prime. The sum of its digits is 10.

In numeral systems, 118 is written as 118 in decimal, CXVIII in Roman numerals, 1110110 in binary, 0x76 in hexadecimal, and 0o166 in octal.

In science, 118 is the atomic number of oganesson, the element with symbol Og. Oganesson is a synthetic, superheavy element in group 18 (the noble gases) and period 7. It was first synthesized by a collaboration between the Joint Institute for Nuclear Research in Dubna and Lawrence Livermore National Laboratory in the early 2000s, with subsequent experiments providing confirmation. The IUPAC approved the name oganesson in 2016, honoring Yuri Oganessian. Oganesson is extremely unstable, with observed lifetimes on the order of milliseconds or less; only a few atoms have ever been produced. Because of relativistic effects in superheavy elements, its predicted properties place it among noble gases, though its behavior may depart from lighter members of the group, and it is expected to be far less reactive than lighter noble gases.

Beyond mathematics and chemistry, 118 can appear in historical year references (for example, 118 CE) and various mathematical contexts as a representative integer. As a number, 118 is notable for its simple factorization and its representations across multiple numeral systems, while as a chemical element it marks the far end of the periodic table’s currently known, highly unstable region.