what 2 prime numbers multiplied together will give you a 400 digit number for the answer?
2007-09-26 04:11:18 · 6 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
10^14 - 29 is a 14-digit prime.
2^1279 - 1 is a 386-digit Mersenne prime.
Their product is:
1040793219466138078
1588787651630327218
920326662460506379
26740500601006
551709174325167
493416724590063
540431923994067
670552333682475
6063963673
927892800853960
190008483086367
9723482154604757
613093273015575613180526
529797348471022
970877005897123
255668411663308
617898265584473
6167634838
7979463856566
6377655655966
4581985575060
4871242259524
7376352154825
86318
3119078122659
624972163544
9589972302584
608106856477
which, as you can readily count, has 400 digits!
If you can find a prime with 399 digits, you can probably just multiply it by 2 or 11.
2007-09-26 04:28:37 · answer #1 · answered by Bryce 2 · 1⤊ 1⤋
There are ten random 200-digit primes at the bottom of the web page below. They are preceded by ten random primes of each of 190, 180, 170 ... digits. The following page begins with 10 random primes of each of 210, 220, 230 ... digits.
Every product of a 200 x 200, or 190 x 210, or 180 x 220, or so on will give you an answer of 400 digits if you just exclude the primes which begin with 1..., 2..., 30... or 31...
Enjoy your multiplications. Oh - here's the link to the page, sorry I omitted it the first time. Chris Caldwell's Prime Pages site is the best resource on the whole world-wide web for anything to do with prime numbers.
2007-09-26 18:23:35 · answer #2 · answered by bh8153 7 · 0⤊ 0⤋
Begin with a Mersenne prime.
http://mathforum.org/library/drmath/view/61527.html
I hope this helps.
Following is a link to a 200 digit composite of two large primes:
http://en.wikinews.org/wiki/200_digit_number_factored
I notice that the two factors need not be the same size. So a 390 digit prime and a 10 digit prime should yield something close to 400 digits. 10 digit primes are easy to generate. That's why you only need to concentrate on finding the special big prime.
2007-09-26 11:23:41 · answer #3 · answered by Anonymous · 1⤊ 1⤋
That's not gonna be a 'unique' solution since, in general, any pair of 200 digit prime number2 will give you a 400 digit answer.
But -finding- 200 digit primes is the real trick âº
Doug
2007-09-26 11:19:14 · answer #4 · answered by doug_donaghue 7 · 1⤊ 1⤋
Well, pick any two prime numbers with 200 digits each.
There are a lot of them. Happy hunting!
2007-09-26 11:14:43 · answer #5 · answered by PMP 5 · 1⤊ 1⤋
400=2^4*5^2
It is not possible to multiply 2 prime numbers to give 400 as their product.
2007-09-26 11:21:02 · answer #6 · answered by Anonymous · 0⤊ 5⤋