Shakuntala Devi was an Indian mathematician who achieved fame for her ability to perform complex mental calculations at incredible speeds. She began demonstrating her mathematical abilities at age 6 and toured internationally in the 1950s and 1970s to showcase her skills. Devi held the Guinness World Record for "Fastest Human Computation" and was able to perform complex calculations like cube roots and large number exponents rapidly in her head. She authored several books and also worked as an astrologer later in life.