World's cleverest man turns down $1million prize after solving one of mathematics' greatest puzzles Last updated at 11:02 PM on 22nd March 2010 No need for greed: A rare photo of bearded and reclusive genius Dr Grigory Perelman An impoverished Russian who has been called the world's cleverest man today said he does not need a $1million prize awarded by a prestigious American institute for solving one of the most intractable problems in mathematics. Dr Grigory Perelman prefers to live as a recluse in his grim cockroach-infested flat in St Petersburg. Told about the financial prize for solving the Poincare Conjecture which had confounded mathematicians for a century, he said through his closed front door: 'I don't need anything. I have all I want.' The bearded genius, aged 44, was named last week as winner of the $1 million prize by the Clay Mathematics Institute in Cambridge, Massachusetts. Four years ago, after posting his solution on the web, he failed to turn up to receive his prestigious Fields Medal from the International Mathematical Union in Madrid. At the time he stated: 'I'm not interested in money or fame. I don't want to be on display like an animal in a zoo. 'I'm not a hero of mathematics. I'm not even that successful, that is why I don't want to have everybody looking at me.' Neighbour Vera Petrovna said: 'I was once in his flat and I was astounded. He only has a table, a stool and a bed with a dirty mattress which was left by previous owners - alcoholics who sold the flat to him. 'We are trying to get rid of cockroaches in our block, but they hide in his flat.' It was in 2003 that Perelman, then a researcher at the Steklov Institute of Mathematics in St. Petersburg, began posting papers online suggesting he had solved the Poincare Conjecture, one of seven major mathematical puzzles for which the Clay Institute is offering $1 million each. Rigorous tests proved he was correct. The topological conundrum essentially states that any three-dimensional space without holes in it is equivalent to a stretched sphere. The puzzle was more than 100 years old when Perelman solved it - and can help determine the shape of the universe. After 2003 Perelman gave up his job at the Steklov Institute. Friends have been reported as saying he has resigned from mathematics altogether - finding the subject too painful to discuss.