Dottie Number represents the unique real fixed point of the cosine function. It is denoted by d and is equal to 0.73908 51332 15160 64165. It was introduced by Kaplan in the year 2007. It is also known as the cosine constant, cosine superposition constant, iterated cosine constant, cosine fixed point constant. It can be defined as unique real root of cos(x) = x or the iteral of cosine.