Indian maths wizard Shakuntala Devi, who died at 83 in the southern Indian city of Bangalore on Sunday, was often called the "human computer".
She made complex mathematical calculations and was a household name in India.
Shakuntala Devi's dazzling computational powers revealed themselves in early childhood but she had no formal education.
Among her adult feats, she was able to multiply two random 13-digit numbers in a few seconds.
She once calculated the 23rd root of a 201 digit number mentally in under a minute.
When given a date in the last century she could instantly calculate which day it fell on.
She was featured by Guinness World Records for this facility with numbers.
"God's gift. A divine quality," said Ms Devi once when she was asked about her ability.
She also said nobody in her family had shown a head for numbers.
"Not even remotely, although my father was a stage magician," she said.
According to reports, he discovered his three-year-old daughter's abilities with numbers when playing cards with her.
He apparently found that she beat him not by sleight of hand, but by memorising the cards.
Devi was already being called a "child prodigy" when, at the age of six, she demonstrated her skills in a public performance at an university in her native state of Karnataka.
DC Shivdev of an education trust run in her name said Shakuntala Devi "strove to simplify math for students and help them get over their math phobia".
He said her "techniques to simplify math were not used by educational institutions".
"It is a pity that her techniques died with her," he told The Hindu newspaper.
Devi wrote a number of books with titles like Fun with Numbers and Puzzles to Puzzle You.
She also had an alternative career as a successful astrologer, and she often toured to give lectures and offered astrology consultations.