115

115 is the natural number that follows 114 and precedes 116. In decimal notation it is written as 115 and is classified as an odd composite number.

Its prime factorization is 5 × 23, making it a semiprime composed of two distinct primes. The divisors of 115 are 1, 5, 23, and 115. The sum of all divisors is 144, while the sum of proper divisors is 29, so 115 is a deficient number (it is smaller than the sum needed for perfectness).

In different numeral systems, 115 appears as 1110011 in binary, 163 in octal, and 0x73 in hexadecimal. In Roman numerals it is written CXV. The decimal 115 corresponds to the lowercase letter 's' in ASCII and Unicode code point U+0073.

115 cannot be expressed as a sum of two squares because its prime factorization includes 23, a prime congruent to 3 mod 4, with odd exponent, which prevents such a representation.

In science, atomic number 115 is Moscovium (symbol Mc), a synthetic superheavy element created by a joint team of researchers at the Joint Institute for Nuclear Research in Dubna and Lawrence Livermore National Laboratory in 2003. Moscovium is highly unstable and has been produced only in very small quantities. It is named after the Moscow Oblast region in Russia; the IUPAC official name was adopted in 2016.

Thus, 115 serves as a straightforward example in number theory as a semiprime and as a reference point in modern chemistry for the designation of a synthetic element.