634

634 is a natural number that follows 633 and precedes 635. In arithmetic, it is even and composite; its prime factorization is 2 × 317, and its divisors are 1, 2, 317, and 634.

In numeral systems, 634 is written as DCXXXIV in Roman numerals; in binary it is 1001111010; in octal it is 1172; and in hexadecimal it is 0x27A.

634 also refers to the calendar year 634 CE in the Julian calendar. It is notable for early Muslim conquests in the Levant during the Byzantine–Rashidun wars. The Battle of Ajnadayn took place in 634, marking a major Muslim victory that helped to open Syria to further campaigns. In the following years, Damascus and Caesarea were captured, and the momentum of the conquests continued toward a decisive phase with the Battle of Yarmouk occurring in 636.