11. It is neither a prime number nor a composite number . 12. Thus it appears that besides 2 and 5, all untouchable numbers are composite numbers . 13. Deterministic algorithms do not erroneously report composite numbers as prime. 14. However, it is the only composite number " n " for which is false. 15. Highly-composite numbers tend to be easily represented in "'primary "'notation. 16. It means that 1, 4, and 36 are the only square highly composite numbers . 17. The Trend Weight combines short, intermediate and long-term trend signals into a single composite number . 18. Additional structure may be seen when composite numbers are also included in the Ulam spiral. 19. No composite number below 2 64 ( approximately 1.845?0 19 ) passes the Baillie-PSW test. 20. Therefore, computing the Kempner function can in general be no easier than factoring composite numbers .