Orders of Magnitude (numbers) - 1018

1018

(1000000000000000000; 10006; short scale: one quintillion; long scale: one trillion)

ISO: exa- (E)

• Computing — Manufacturing: An estimated 6×1018 transistors were produced worldwide in 2008.
• Computing — Computational limit of a 64-bit CPU: 9,223,372,036,854,775,807 (about 9.22×1018) is equal to 263-1, and as such is the largest number which can fit into a signed (two's complement) 64-bit integer on a computer.
• Mathematics — NCAA Basketball Tournament: There are 9,223,372,036,854,775,808 (263) possible ways to enter the bracket.
• Mathematics — Bases: 9,439,829,801,208,141,318 (≈9.44×1018) is the 10th and largest number with more than one digit that can be written from base 2 to base 18 using only the digits 0 to 9.
• BioMed — Insects: It has been estimated that the insect population of the Earth is about 1019.
• Mathematics — Answer to the wheat and chessboard problem: When doubling the grains of wheat on each successive square of a chessboard, beginning with one grain of wheat on the first square, the final number of grains of wheat on all 64 squares of the chessboard when added up is 264−1 = 18,446,744,073,709,551,615 (≈1.84×1019).
• Mathematics — Legends: In the legend called the Tower of Brahma about a Hindu temple which contains a large room with three posts on one of which is 64 golden discs, the object of the mathematical game is for the Brahmins in the temple to move all of the discs to another pole so that they are in the same order, never placing a larger disc above a smaller disc. It would take 264−1 = 18,446,744,073,709,551,615 (≈1.84×1019) turns to complete the task (same number as the wheat and chessboard problem above).
• Mathematics — Rubik's Cube: There are 43,252,003,274,489,856,000 (≈4.33×1019) different positions of a 3x3x3 Rubik's Cube
• Password strength: Usage of the 95-character set found on standard computer keyboards for a 10-character password yields a computationally intractable 59,873,693,923,837,890,625 (9510, approximately 5.99×1019) permutations.
• Economics: Hyperinflation in Zimbabwe estimated in February 2009 by some economists at 10 sextillion percent, or a factor of 1020