In mathematics a prime number is the natural number that has no positive factors other than 1 and itself. As natural numbers greater than 1 can be factored characterized by prime numbers, identities of a culture could be understood if its cultural phenomena are analyzed through cultural prime numbers(CPN). It is not easy to resolve cultural phenomena into CPN and analyze them through CPN due to complexities of culture. Though it is difficult, however, it is not impossible. For CPN keeps relative independence in the context of history and thought. We call 2, 3 and 5 as CPN: 2 is representative of Yin and Yang theory, 3 of Three Principles theory, and 5 of Five Elements theory. We argue that the Ten Celestial Stems and the Twelve Earthly Branches, the core principles in the oriental tradition, could be factored by the CPN. Analyzing Sil-Hah Woo's arguments, we discuss that the CNP 3 achieved more qualitative valuation than the others in Korean culture.