126

126 is a natural number that follows 125 and precedes 127. In mathematics, it is an even composite number with prime factorization 2 × 3^2 × 7. Its positive divisors are 1, 2, 3, 6, 7, 9, 14, 18, 21, 42, 63, and 126. The sum of its proper divisors is 186, which classifies 126 as an abundant number. It has 12 divisors in total. In different numeral systems, 126 is 1111110 in binary, 7E in hexadecimal, and 176 in octal. In Roman numerals it is CXXVI. In combinatorics, 126 appears as the binomial coefficient C(9,4) = 126 (also C(9,5) = 126).

126 also has cultural and astronomical associations. It is the designation of asteroid 126 Heracles, a large main-belt asteroid discovered in 1872 by Johann Palisa and named after Hercules. In calendar history, the year AD 126 is associated with the reign of Emperor Hadrian, during which notable rebuilding of the Pantheon in Rome took place. In computing, decimal 126 corresponds to the tilde character ~ in the ASCII character set.

Overall, 126 is a multifaceted number with clear mathematical properties and several notable references in history, astronomy, and computing.