28000

28000 is the natural number that follows 27999 and precedes 28001. It is an even, composite integer. In prime factorization terms, 28000 = 2^5 × 5^3 × 7, which means it is divisible by 2, 4, 5, 7, 8, 10, 14, 16, 20, 25, 28, 32 and other multiples. It can be expressed as 28 × 1000, highlighting its status as a round figure in decimal notation. The sum of its digits is 10, so it is not divisible by 3 or 9, while the last three digits being 000 confirms divisibility by 8, 16 and 32.

In number theory terms, 28000 is a definite composite number with a nontrivial prime decomposition (2^5 × 5^3 × 7). It is not a prime, nor a perfect square, nor a triangular number. Its factorization shows it is divisible by 7 and by high powers of 2 and 5, but it is not a power of two or a simple power of another integer.

28000 also appears in geography as a postal code. In France, 28000 is the postal code for Chartres, a city in the Eure-et-Loir department in the Centre-Val de Loire region. The department code 28 identifies Eure-et-Loir, and the 28000 code covers Chartres city center and nearby areas. Chartres is renowned for its historic cathedral and other medieval architecture.

Beyond geography, 28000 is commonly cited as a round-number figure in various counting, measurement, and statistical contexts due to its multiples of 1000 and its convenient factorization.