Take one blackboard, one piece of chalk, 1,257,787 twos and work out a world record (don't forget to subtract one)
Thursday 05 September 1996
Prime numbers - those that can be divided without remainder by no whole numbers other than one and themselves - have fascinated mathematicians for more than 2,000 years. Euclid provided the first simple proof that there is an infinity of primes. (If not, just multiply them all together and add one. The resulting number is either itself prime or has a prime divisor different from those you started with. QED.)
For the last 100 years, we have even known roughly how many prime numbers there are below any given figure. (This is given by the so-called prime number theorem, first proved in 1896.) Yet despite knowing there is no largest prime, people have continued searching for ever larger ones.
In 1772, the record was held by a 10-digit number; by 1884, it had been raised to 20 digits, but the real acceleration began in the computer age. In 1971, months of computer calculations led to the discovery of a 6,002- digit prime, and in the 1980s and 90s Cray computers have been pushing the record higher almost every year.
A spokesman for Cray described prime testing as a "torture test" for supercomputers. Others might call it a waste of time. Recently, however, the task of factorising large numbers has had important applications in computer security.
We had intended to print the new top prime in full, but - perhaps for reasons of security - the people at Cray have not divulged all its digits. Of course, you can work it out yourself: just take 1,257,787 twos, multiply them together and subtract one from the answer.
- 1 Notting Hill Carnival: Woman shares selfie after being ‘punched in face for telling man to stop groping her’
- 2 Keira Knightley topless: Usually conservative actress does own take on #Freethenipple campaign for Interview Magazine
- 3 Daily Show's Jon Stewart destroys Fox News for its Ferguson coverage
- 4 When elitism grips the top of British society to this extent, there is only one answer: abolish private schools
- 5 Brother and sister, Christopher Buckner and Timothy Savoy, arrested for 'committing incest after watching 'The Notebook''
Ashya King missing: Police hunt five-year-old boy with brain tumour snatched from Southampton hospital by his parents
Keira Knightley topless: Usually conservative actress does own take on #Freethenipple campaign for Interview Magazine
YouTube video posted by Isis militants shows 'execution of 250 Syrian soldiers'
Botched ice bucket challenge leaves man critically injured after plane drops hundreds of gallons of water
Papua New Guinea Mount Tavurvur volcano eruption sees international flights diverted
Exclusive: We share blame for creating 'jihad generation', says Muslim strategist
Robin Williams Emmys tribute led by Billy Crystal criticised for including 'racist' joke about Muslim woman
The Rotherham child abuse scandal is a tale of apologists, misogyny and double standards
Scottish independence TV debate: Pumped-up Alex Salmond bounces back in bruising second round against Alistair Darling
Do you realise just how foolish the UK looks?
Ukip Douglas Carswell defection: Tory MP jumps ship to join Nigel Farage
- < Previous
- Next >
£350 - £400 Per Day: Clearwater People Solutions Ltd: Our client based in Cent...
£17000 - £20000 Per Annum Bonus, Life Insurance + Other Benefits: Clearwater P...
£450 - £500 per day: Orgtel: SAS Business Analyst, London, Banking, Credit Ris...
£32000 - £38000 Per Annum Bonus, Life Insurance + Other Benefits: Clearwater P...