394

394 is the natural number that follows 393 and precedes 395. It is an even, composite number. Its prime factorization is 2 × 197, with 197 being a prime, so 394 is a semiprime. The positive divisors of 394 are 1, 2, 197, and 394. The digits sum to 16, and the digital root is 7. In Roman numerals, 394 is written as CCCXCIV.

In mathematics, 394 serves as an example of a semiprime, a product of two primes, in this case 2 and 197. It is not a prime, not a square, and has exactly four positive divisors. Its properties make it a straightforward case study in prime factorization and divisor counting within elementary number theory.

Historically, the year AD 394 saw the Battle of the Frigidus, fought between Roman emperor Theodosius I and the usurper Eugenius near the Frigidus River in Noricum. Theodosius's victory ended the civil conflict and restored him as the sole ruler of a united Roman Empire until his death in 395. Upon his death, the empire was inherited by his sons Arcadius in the East and Honorius in the West, marking the permanent administrative division of the empire into eastern and western realms.