390

390 is a natural number that comes after 389 and before 391. In prime factorization, 390 = 2 × 3 × 5 × 13, a product of four distinct primes. As a result, it has 16 positive divisors and is an even composite number.

Roman numerals: 390 is written CCCXC.

In calendar terms, 390 BCE is noted for the sack of Rome by the Gauls under Brennus, which led to major Roman military and urban reforms in the subsequent centuries.

Asteroid 390 Alma is a large body in the main asteroid belt. It is the 390th asteroid to be cataloged and was discovered in 1894 by Auguste Charlois. The asteroid is named Alma.

Geometrically, 390 degrees is equivalent to 30 degrees beyond a full turn, since 390 − 360 = 30.