69

69 is a natural number that follows 68 and precedes 70. It is an odd composite number with prime factorization 3 × 23, and its divisors are 1, 3, 23, and 69. In decimal notation it is written as 69; in other bases it appears as 1000101 in binary, 105 in octal, and 45 in hexadecimal. The Roman numeral representation is LXIX.

Additionally, 69 is the atomic number of the lanthanide thulium. In mathematics it is a semiprime, being the product of two primes (3 and 23).

Historically, AD 69 is known as the Year of the Four Emperors in the Roman Empire, a chaotic year following the end of Nero's reign. The year 1969 is notable in modern history for events such as the first moon landing, the Apollo 11 mission, and the Woodstock festival, among others.

In popular culture, the number 69 is widely recognized as a reference to a sexual position; its use is often humorous or suggestive, depending on context. The dual cultural resonance of the number reflects its occurrence both as a mathematical integer and as a symbol in contemporary media.