Number Recreations

Shyam Sunder Gupta
Director(Railways and Metros),
Consulting Engineers Group, Jaipur, India-302017

What is New? (Update 17 June, 2020)

The page on Rare Numbers updated (including list up to 1023).

Prime curios 11, 1427, 44936, 120689, 132882, 480585, 206913578, 511733945 and many more added.

Do You Know?

The product of four consecutive positive integers can not be equal to product of two consecutive positive integers.

Can You Find?

CYF NO. 53
The two primes p and q such that sum of primes from p to q is equal to product of p and q, where q > p > 10.

email your answer


Note: The above topics including many more will be added in due course.


My Contributions in Prime Curios

Prime Curios! - site maintained by G. L. Honaker Jr. and Chris Caldwell

My Favorite Links

  • Magic Squares,Magic Stars and Other Interesting number patterns by Harvey Heinz
  • Mudd Math Fun Facts pages
  • On-Line Encyclopedia of Integer Sequences OEIS
  • Math Puzzles
    An interesting site with lot of math recreations by Ed Pegg Jr.

My Favorite Books

Recommended list of books for those interested in Recreational and Computational Number theory
In Association with In Association with

The Rail
(January, 2003)

(March, 2003)
The Busy Educator Award
(October, 2003)

Send me e-mail at

This page was last updated on 17th June, 2020.

Copyright 2001-2020 Shyam Sunder Gupta. All rights reserved.