The IBM 1620 was a decimal computer introduced by IBM in 1959, primarily designed for scientific and engineering calculations. It was notable for its use of magnetic core memory and its ability to perform calculations using decimal rather than binary, making it more accessible for users familiar with traditional arithmetic. The IBM 1620 featured a simple programming model and was often used in educational institutions for teaching programming and computing concepts. Its affordability and ease of use contributed to its popularity, leading to widespread adoption in various fields until it was eventually phased out in the late 1970s.