The binary number "10001001" is an 8-bit sequence used in digital computing and electronics. Each digit in this sequence represents a power of 2, starting from the rightmost digit, which is 2^0. In decimal form, "10001001" equals 137, as it can be calculated by adding the values of the bits that are set to 1. In computer systems, binary numbers like "10001001" are fundamental for data representation and processing. They are used in various applications, including programming languages, data storage, and communication protocols. Understanding binary is essential for fields such as computer science and information technology.