The number "217" is an integer that follows 216 and precedes 218. It is an odd number and can be expressed as the sum of two prime numbers: 107 + 110. In mathematics, it is often used in various calculations and can be found in different contexts, such as statistics and coding. In the context of area codes, 217 is the telephone area code for parts of central Illinois, including cities like Champaign and Springfield. This area code was established in 1947 and is part of the North American Numbering Plan, which organizes telephone numbers in the United States.