Yes, 11 is a rational number.
Rational numbers are defined as numbers that can be expressed as the quotient of two integers, where the denominator is not zero. In this case, the number 11 can be written as 11/1, which clearly shows that it is the ratio of two integers: 11 (the numerator) and 1 (the denominator).
Additionally, any whole number, like 11, is also considered a rational number because it can be represented in this way. Therefore, 11 is indeed a rational number.