The Penguin Dictionary of Curious and Interesting NumbersWhy was the number of Hardy's taxi significant? Why does Graham's number need its own notation? How many grains of sand would fill the universe? What is the connection between the Golden Ratio and sunflowers? Why is 999 more than a distress call? All these questions and a host more are answered in this fascinating book, which has now been newly revised, with nearly 200 extra entries and some 250 additions to the original entries. From minus one and its square root, via cyclic, weird, amicable, perfect, untouchable and lucky numbers, aliquot sequences, the Cattle problem, Pascal's triangle and the Syracuse algorithm, music, magic and maps, pancakes, polyhedra and palindromes, to numbers so large that they boggle the imagination, all you ever wanted to know about numbers is here. There is even a comprehensive index for those annoying occasions when you remember the name but can't recall the number. 
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Review: The Penguin Dictionary of Curious and Interesting Numbers
User Review  Patrick  GoodreadsThis book is wonderful for skimming. And something about its direct, mathematical style is very funny to me. I sometimes wonder if mathematics might not be the best training for writing terse ... Read full review
Review: The Penguin Book of Curious and Interesting Numbers: Revised Edition
User Review  Greg Ross  GoodreadsThis book does what a good popular math book ought to  it conveys the author's love of the subject without seeming to compromise or condescend to the general reader. Essentially it's one long list ... Read full review
Common terms and phrases
2digit 4digit number 4th powers abundant number amicable numbers approximation Archimedes arithmetical progression base binary calculated circle conjectured consecutive integers consecutive numbers counting cube cyclic permutation David Slowinski diagonals discovered distinct primes divided divisors dodecahedron equal equation Euler example Fermat number Fibonacci numbers Fibonacci sequence form 4n formula Golden Ratio googol Greeks hexagonal number integers JRM v22 Kaprekar Kaprekar number large numbers largest number length Lucky numbers magic square mathematicians mathematics Mersenne number Mersenne prime multiple negative numbers notation number of digits number of primes Number Theory numbers less odd number palindromic prime pandigital Pascal Pascal's triangle pattern perfect number Plato Platonic solids polygons prime factors prime number primorial problem proved Pythagorean triangle reciprocal repeated represented repunit Ribenboim rightangled triangle sequence of numbers Sloane smallest number solution square root starts Subfactorial tetrahedral number theorem triangular numbers unit fractions values whole numbers zero