**Avogadro’s number = 6.0221415 × 10^23** This was recently used in the book “True Evil” by Greg Iles. Apparently you learn this number in high school if you take chemistry. I never took chemistry and so I am just now learning about it.

**The Fibonacci Sequence **0, 1, 1, 2, 3, 5, 8, 13, … (add the last two to get the next) Used in Dan Brown’s book The Da Vinci Code. Brown also used Phi which is 1.618 which is also referred to as the golden number or the divine proportion.

**23** – The Ancient Chinese believed numbers conveyed sexuality – evens for feminine and odds for masculine. They considered prime numbers to be the most masculine, conferring special status on 23 which is made up of two consecutive prime numbers and the only even prime number – two.

**3** – represents the Trinity: Father, Son and Holy Spirit.

**7** – For Christians this is God’s number, some people think of 7 as lucky.

**666** – The mark of the beast. “He also forced everyone, small and great, rich and poor, free and slave, to receive a mark on his right hand or on his forehead so that no one could buy or sell unless he had the mark, which is the name of the beast or the number of his name. This calls for wisdom. If anyone has insight, let him calculate the number of the beast, for it is man’s number. His number is 666” (Rev. 13:16-18).

**13** – unlucky

**4** – in Chinese the pronunciation of the number 4 and the word for death are very similar and therefore the number 4 is unlucky.

**Pi – 3.14** proper pronunciation is pee in Greek. Pi or ? is one of the most important mathematical constants, approximately equal to 3.14159. It represents the ratio of any circle’s circumference to its diameter in Euclidean geometry.

**E – 2.718** The number e is occasionally called Euler’s number after the Swiss mathematician Leonhard Euler, or Napier’s constant in honor of the Scottish mathematician John Napier who introduced logarithms. The mathematical constant e is the unique real number such that the value of the derivative (slope of the tangent line) of f(x) = ex at the point x = 0 is exactly 1. The function ex so defined is called the exponential function, and its inverse is the natural logarithm, or logarithm to base e.