Shakuntala Devi
Shakuntala Devi (Born 1939 born in Bangalore, India) is an Indian mathematician often referred to as a "human calculator". She demonstrated the multiplication of two 13-digit numbers 7,686,369,774,870 x 2,465,099,745,779 picked at random by the Computer Department of Imperial College, London, on June 18, 1980 in 28 seconds. Her correct answer was 18,947,668,177,995,426,462,773,730.
In 1977, she extracted the 23rd root of a 201-digit number mentally. At the age of six, Shakuntala demonstrated her talents at the University of Mysore, before a huge gathering of professors and students of higher studies in mathematics. With lightning rapidity and precision, she declared right answers mentally working out calculations for the most complicated problems. At the age of eight, she thrilled the learned audience of Annamalai University