945

945 is the natural number that follows 944 and precedes 946. In mathematics, it is an odd composite number with prime factorization 3^3 × 5 × 7, which gives it 16 positive divisors. It is divisible by 3, 5, 7, and by 9, as well as by many of their multiples, reflecting its factor structure. The digit sum is 18, so it is divisible by 9 but not by 18. Its representations in different numeral systems include Roman numerals as CMXLV, binary as 1110110001, and hexadecimal as 0x3B1.

In calendar history, 945 AD falls within the period known in Chinese history as the Five Dynasties and Ten Kingdoms. During that year, the Khitan-led Liao Dynasty conducted campaigns against the Later Jin and captured Kaifeng, the Later Jin capital. This campaign contributed to the weakening and eventual collapse of the Later Jin, which ended a few years later, helping shape the northern Chinese political landscape before the rise of later regimes and, eventually, the Song Dynasty.

Beyond historical and mathematical contexts, 945 is used as a numeric label in various systems, dates, and identifiers. It does not denote a single universally recognized event or constant, but rather serves as a representative three-digit integer with distinct factorization and historical associations in certain eras.