1015
(1000000000000000; 10005; short scale: one quadrillion; long scale: one thousand billion, or one billiard)
ISO: peta- (P)
- BioMed-Insects: 1,000,000,000,000,000 to 10,000,000,000,000,000 (1015 to 1016) – The estimated total number of ants on Earth alive at any one time (their biomass is approximately equal to the total biomass of the human race).
- Computing: 9,007,199,254,740,992 (253) – number until which all integer values can exactly be represented in IEEE double precision floating-point format.
- Mathematics: 48,988,659,276,962,496 is the fifth taxicab number.
- Science Fiction: In Isaac Asimov's Galactic Empire, in what we call 22,500 CE there are 25,000,000 different inhabited planets in the Galactic Empire, all inhabited by humans in Asimov's "human galaxy" scenario, each with an average population of 2,000,000,000, thus yielding a total Galactic Empire population of approximately 50,000,000,000,000,000.
- Cryptography: There are 7.205759×1016 different possible keys in the obsolete 56 bit DES symmetric cipher.
Read more about this topic: Orders Of Magnitude (numbers)