Prime Factors Calculator

This site uses cookies; click here for details.
If you continue to use this site I'll assume you're happy to accept this.
Site Home

Maths Home

Site Index

Calculator Index

About Us

Privacy Policy

This calculator will calculate the prime factors of a positive integer. The algorithm used can, in theory, handle very large numbers but beware that numbers with large prime factors could take a long time to factorise. For example, 1234567890123456789012345678901234567890 factorises almost instantly, whereas 12345678901234567 takes a lot longer, because, even though smaller, one of the prime factors is a large number.

The previous version of this page is available here and is probably faster if you can run unsigned Java applets


Number to factorise:




This page uses Tom Wu's JSBN library. Please see the JSBN licence here


Whilst I try to keep the information on this site accurate, I'm only human and I do occasionally make mistakes. I therefore advise you to check any information before using it for anything important. If you do find any errors, please let me know so that I can correct them.

Click here to report an error on this page.

This page was last changed on: 04 December 2017.

Thanks for visiting my site.