hello I am new here
 

I wanted to ask if 73786976290543239167 is prime.:smile:

Nope, 73786976290543239167 = 3391 * 12113 * 14369 * 125018321

Alex

[B]n1994[/B]

Welcome to Mersenne Forum!

You can ask us about primality of much larger numbers. :smile:

To factor small numbers (anything below 10^40 or so), google "ecm factoring". The first link is to a java applet that factors small numbers very quickly. Numbers larger than 10^40 can also be done, but may take a while (the larger the number, the longer the factoring process may take). Numbers of the size you originally asked about take seconds.
-Curtis

thanks
 

I want to ask you about
18889465931478580871167
and how do you check if its prime?

and
 

885470737341981130751

last numbers:
23611832414348226068479

[quote=n1994;128493]last numbers:
23611832414348226068479[/quote]
Please find it for yourself, using VBCurtis's instructions (below).
[quote=VBCurtis;128458]To factor small numbers (anything below 10^40 or so), google "ecm factoring". The first link is to a java applet that factors small numbers very quickly. Numbers larger than 10^40 can also be done, but may take a while (the larger the number, the longer the factoring process may take). Numbers of the size you originally asked about take seconds.
-Curtis[/quote]
[SIZE=1]c.f. vg'f cevzr[/SIZE]

[QUOTE=n1994;128493]last numbers:
23611832414348226068479[/QUOTE]You can even go here also:

[url]http://wims.unice.fr/wims/wims.cgi?module=tool/algebra/factor.en[/url]

[QUOTE=Mini-Geek;128494]Please find it for yourself, using VBCurtis's instructions (below).

[SIZE=1]c.f. vg'f cevzr[/SIZE][/QUOTE][SIZE=1]Unun, lrnu vg vf cevzr, fb rnfl gb purpx.[/SIZE]

Here's another good page to factor numbers: [url]http://www.alpertron.com.ar/ECM.HTM[/url]

Alex

[QUOTE=akruppa;128508]Here's another good page to factor numbers: [url]http://www.alpertron.com.ar/ECM.HTM[/url][/QUOTE]That page ain't so good because it needs either java or javascript to work.

sory but i need a big prime checker
 

thanks for the last prime checker but now I need a 149 number.
can someone help me?
67039039649712985497870124991029230637396829102961966888617807218608820150367734884009371490834517138450159290932430254268769414059732849732168245030420479

[quote=n1994;128544]thanks for the last prime checker but now I need a 149 number.
can someone help me?
[number clipped out][/quote]
[URL]http://pari.math.u-bordeaux.fr/download.html[/URL]
Try using PARI/GP to factor your numbers. Use the factor(x) command (or, if you only need to know primality, use isprime(x), or ispseudoprime(x) if you want it faster but don't need to be 100% sure it's correct).
Why do you need to know if all these numbers are prime or not?

That number has 155 digits. Coincidentally, it contains a 149 digit (probable) prime

the small factors are:
691 and 8941

ohh i counted 149 and are u sure its not prime?

please can someone give me a softare
161585030356555036503574383443349759802220513348577420160651727137623275694339454465986007057614567318443589804609490097470597795752454605475440761932241415603154386836504980458750988751948260533980288191920337841383961093213098780809190471692380852352908229260181525214437879457705329043037761995619651927609571666948341712103424873932822847474280880176631610290389028296655130963542301570751292964320885583629718018592309286787991755761508229522018488066166436156135628423554101048625785508634656617348392712903283489675229986341764993191077625831947186677718010677166148023226592393024760740967779268055297981153279

[quote=n1994;128559]please can someone give me a softare
161585030356555036503574383443349759802220513348577420160651727137623275694339454465986007057614567318443589804609490097470597795752454605475440761932241415603154386836504980458750988751948260533980288191920337841383961093213098780809190471692380852352908229260181525214437879457705329043037761995619651927609571666948341712103424873932822847474280880176631610290389028296655130963542301570751292964320885583629718018592309286787991755761508229522018488066166436156135628423554101048625785508634656617348392712903283489675229986341764993191077625831947186677718010677166148023226592393024760740967779268055297981153279[/quote]
I already have. PARI/GP.
[url]http://pari.math.u-bordeaux.fr/download.html[/url]
Download it. It's not that hard to use.

but it doesnt let me download it
 

???

[quote=n1994;128558]ohh i counted 149 and are u sure its not prime?[/quote]

you counted? as in by sight, digit by digit? Bravo to your patience, if so, but I'll trust my program which says 155 digits.

I'm sure its not. It has the factors I stated. You can check this for yourself using the program mentioned in this thread, or use bc ([URL]http://gnuwin32.sourceforge.net/packages/bc.htm[/URL]).

[edit]
your last (annoyingly, for my browser) long number is also not prime.

[quote=n1994;128562]???[/quote]
[URL]http://pari.math.u-bordeaux.fr/pub/pari/windows/Pari-2-3-3.exe[/URL]
1. Download that.
2. Install it.
3. Run gp.exe.
4. Type "isprime(", then copy your long number and paste it in by clicking the C:\ icon in the upper left corner, going to Edit, and clicking Paste (Ctrl+V doesn't work in GP, and right click is disabled), then press ")" and click Enter.
5. See that it says 0, meaning not prime.
6. Stop posting here about things you can obviously find on your own.
If you do need to post another long number, please use the [ code ][ /code ] tags so it doesn't make the page extremely long.

[quote=Mini-Geek;128567][URL]http://pari.math.u-bordeaux.fr/pub/pari/windows/Pari-2-3-3.exe[/URL]
1. Download that.
2. Install it.
3. Run gp.exe.
4. Type "isprime(", then copy your long number and paste it in by clicking the C:\ icon in the upper left corner, going to Edit, and clicking Paste (Ctrl+V doesn't work in GP, and right click is disabled), then press ")" and click Enter.
5. See that it says 0, meaning not prime.
6. Stop posting here about things you can obviously find on your own.
If you do need to post another long number, please use the [ code ][ /code ] tags so it doesn't make the page extremely long.[/quote]

thanks last problem' can i copy anumber into it with out writing it

[quote=n1994;128569]thanks last problem' can i copy anumber into it with out writing it[/quote]
I...told...you...how...to...paste...
Once you copy it (you can copy it from this thread, if you like), after you've put the "isprime(" (or "factor(" or "ispseudoprime(" or whatever other command), click the C:\ icon in the upper left of the GP window, go to Edit, and click Paste.

I think there's a language barrier here, which seems to be what is causing much of the problem.

n1994, what is your native language?

We have people from everywhere in the forum so if you'd like to converse with someone by private message in something other then English, that might help a lot.

For my own curiosity, for the original numbers shown here that no one has posted the factors for, I looked at them using Alpterton's site that was posted by akruppa that I have used many times in the past:

18889465931478580871167 = 7 * 31 * 151 * 2092667 * 275475431603
885470737341981130751 is prime
23611832414348226068479 is prime

-and-

[code]
67039039649712985497870124991029230637396829102961966888617807218608820150367734884009371490834517138450159290932430254268769414059732849732168245030420479 = 691 * 8941 * 10850847054717278375941288856151417879551093039894747685642995093354201251194352377567198683706471502676115427042535355875940769139213611425692604409
[/code]

Two communication issues here:

1. The 149-digit factor is a PROVEN prime, not just a probable prime. I think that is what N1994 was asking when he said "r you sure its not prime" in response to bsquared saying it was a (probable) prime.

2. When N1994 said it was a 149-digit number, it was the factor he was referring to, not the original 155-digit number.

So in response to the N1994 post of 11 Mar 08 at 7:44 PM GMT, yes the FACTOR is 149 digits and that factor IS prime! :smile:

-and-

[code]
161585030356555036503574383443349759802220513348577420160651727137623275694339454465986007057614567318443589804609490097470597795752454605475440761932241415603154386836504980458750988751948260533980288191920337841383961093213098780809190471692380852352908229260181525214437879457705329043037761995619651927609571666948341712103424873932822847474280880176631610290389028296655130963542301570751292964320885583629718018592309286787991755761508229522018488066166436156135628423554101048625785508634656617348392712903283489675229986341764993191077625831947186677718010677166148023226592393024760740967779268055297981153279 = 7951 * 178691 * 1142891 * 11056621 * C595
[/code]
C595 = 595-digit composite factor. Tested to curve 30 on Alperton's site.

Edit: Like most everyone else, I'm STILL curious where N1994 is getting these numbers from!


Gary