Dattaraya Ramchandra Kaprekar was born on January 17, 1905, at Dahanu, near Bombay. His mother died when he was barely eight years old. His father, who was clerk, brought him up as best as he could. The clerk might not have known much of mathematics, but astrology was his hobby and he taught the child that.
Astrology introduced Kaprekar to the world of numbers. Calculations thrilled him. He started trying to find the shortest possible routes to solve mathematical problems. He used to spend hours solving mathematical puzzles and problems. In 1927 he won the Wrangler R. P. Paranjpe Mathematical Prize for an original piece of work in mathematics. In 1929 he took his B.Sc. from the Fergusson College in Pune and became a school teacher.
What is the “Kaprekar constant” that he discovered in 1946? It is the number 6174. To see how it is constant, take any four digit number in which not all digits are alike. Arrange the digits in descending order and reverse them to make a new number. If this process is repeated with the remainders, eventually, say, in eight steps or more, the constant 6174 is arrived at and this number then itself.
The procedure may seem easy now, but it took Kaprekar three years of labour and patience to arrive at the constant. He began calculations from a lower number and went on till he found the constant.
One set of numbers called “self numbers” is also known by his name. These are, so to say, self-born numbers. Kaprekar is also recognized for his significant contributions to Demlo numbers and other recreational mathematics problems. He has written books on his discoveries.