BIG numbers hold no fear for Samuel Wagstaff. When not teaching computer
science at Purdue University in Indiana, Wagstaff coordinates international
assaults on the record for the largest number ever factorised.
Wagstaff and his team of number crunchers have now split a 167-digit number
into its component factors. The number is (3349鈭�1)/2鈥攚ritten out in full
above with its 80 and 87-digit factors. Finding the factors took 100 000 hours
of computing time. The previous factorisation record was held by a number that
was a puny 162 digits long.
For the past 15 years, Wagstaff has kept a list of large numbers that have
resisted factorisation. His group is now crunching other numbers up to 195
digits long. Cracking a 200-digit number remains a dream, however. 鈥淚t would
take us about a year,鈥� says Wagstaff. 鈥淏ut if we have more people helping us,
perhaps we could do it quicker.鈥�
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