Ok this question really has me stumped:?

Question

Problem: Find two prime numbers that, when multiplied, produce a 400 digit number.

...Has anyone even seen a 400 digit number? What would you call that number? Anyways its obvious that you would have to work with scientific notation, but I dunno what forrmula/strategy to even try...

BTW, I posted this question under computer security and under math because I know this deals with the basics of computer encryption. This is actually a course in my I.S.S. program...

Answer 1

716111958663682417342303150142 608858901789417310093684696588 037024637209566331209352948311 017575749961619319828641955426 693304570465688762892415366806 836017495077860594429200032782
63334056542642264651

X

580216645856397911811840259504 402483982261360695169382324936 875058224718365368242988227337 103422506977399968259382326419 406708576245141031259861340509 976971601273015479957884681378
87651823707102007839

=

415500078713497281558905442483 784251718409580288016708180261 624957845916174034681385215800 377996269949769240101176290536 233429600607265291665503850867 426580947888398820550079218757 303625094649132652959885439006 834654658500398125929731018350 466670499118257135230989594968 432239652495895326959857212205 024845334097138922197109779294 150585092298147887850145072541 456311267636214499699970863002
4114599189

Try http://world.std.com/~reinhold/BigNumCalc.html
for a calculator which will generate large prime numbers as well as multiply two large numbers together.

Answer 2

Here's a link to a page with a lot of information about how they figure out very large prime numbers. This is impossible without a computer. They actually have found primes that are far far longer than 400 digits! I hope this information helps you with your project.

Answer 3

I don't have a prime calculator, but this site will give you 10 200-digit roots.