112

112 is a natural number that follows 111 and precedes 113. In base-10 arithmetic it is even and composite, with prime factorization 2^4 × 7. It can be represented in other bases as well, for example 1110000 in binary, and in Roman numerals as CXII.

The number 112 is widely known for its use as an emergency telephone number in many parts of the world. It was standardized by the International Telecommunication Union (ITU) and is part of the E.164 international numbering plan under the E.112 specification. In the European Union, 112 is the standard pan-European emergency number and can be dialed free of charge on fixed or mobile networks to reach police, fire, or medical services. In many countries outside the EU, 112 is recognized as an emergency number and may be used alongside national numbers such as 911 or 999. On many mobile devices, dialing 112 can work even without a SIM card or when the device is locked, and modern networks and dispatch centers may provide callers with location information to assist responders. Availability and precise routing of 112 calls vary by country and operator.

Historically and culturally, 112 also appears as a calendar year (112 CE/AD) and may be encountered in various numbering or cataloging systems that assign 112 as a code or identifier in country-specific contexts.