Number Recreations

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

What is New? (Update 14 December, 2019)

The page on Rare Numbers updated (including list up to 1022).

CYF NO. 49 Comments by Daniel Suteu given.

CYF NO. 51 Comments by Jens Kruse Andersen given.

Prime curios 12, 182, 10342, 49141, 10234567 and many more added.

Do You Know?

The number 665067264 is the largest even number such that the number formed from first n digits is divisible by nthprime.

Can You Find?

CYF NO. 52
The smallest sets of 13, 14 and 15 consecutive primes which are emirps also.

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 14th December, 2019.

Copyright 2001-2019 Shyam Sunder Gupta. All rights reserved.