# Number of atoms in

In science, number of atoms in (something), such as 'one human', 'the earth', 'the sun', 'the galaxy', 'the universe', among other varieties, is a popular search query. The following table lists some of these atomic counts. [1] The third column, Exp, shows the old-fashioned calculator shorthand symbol for large numbers, in which E is short for exponent, in the sense that, for instance, E9 is short for 10E9 which is short for $10^9 \,$.

 # Name Number written out Exp Number of atoms in 1 one 1 $H \,$ 2 two 2 $H_2 \,$ 3 three 3 $H_2 O \,$ $10^2 \,$ hundred 100 E2 $10^3 \,$ thousand 1,000 E3 $10^6 \,$ million 1,000,000 E6 $10^9 \,$ billion 1,000,000,000 E9 (ten) bacteria molecules $10^{12} \,$ trillion 1,000,000,000,000 E12 $10^{15} \,$ quadrillion 1,000,000,000,000,000 E15 (ten) pre-aquatic worms $10^{18} \,$ quintillion 1,000,000,000,000,000,000 E18 $10^{21} \,$ sextillion 1,000,000,000,000,000,000,000 E21 (one) small fish $10^{24} \,$ septillion 1,000,000,000,000,000,000,000,000 E24 Avogadro's number $10^{27} \,$ octillion 1,000,000,000,000,000,000,000,000,000 E27 (one) human molecule (person) $10^{30} \,$ nonillion 1,000,000,000,000,000,000,000,000,000,000 E30 $10^{33} \,$ decillion 1,000,000,000,000,000,000,000,000,000,000,000 E33 $10^{36} \,$ undecillion 1,000,000,000,000,000,000,000,000,000,000,000,000 E36 $10^{39} \,$ duodecillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000 E39 $10^{42} \,$ tredecillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000 E42 $10^{45} \,$ quattuordecillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 E45 $10^{48} \,$ quindecillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 E48 $10^{51} \,$ sexdecillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 E51 (one) earth molecule (the earth) $10^{54} \,$ septendecillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 E54 $10^{57} \,$ octodecillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 E57 (one) sun molecule (the sun) $10^{60} \,$ novemdecillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 E60 $10^{63} \,$ vigintillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000 E63 $10^{66} \,$ unvigintillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000 E66 the milky way galaxy $10^{69} \,$ duovigintillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000 E69 $10^{72} \,$ tresvigintillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000 E72 $10^{75} \,$ quattuorvigintillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000 E75 $10^{78} \,$ quinquavigintillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000 E78 $10^{81} \,$ sesvigintillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000 E81 the observable universe $10^{84} \,$ septemvigintillion 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000, 000,000,000,000,000,000,000,000 E84

Multiverse
At the high end of the hypothetical estimates and speculative theories is the idea that the observable universe is connected to other 'parallel universes', possibly via wormholes (or other contrivances), such that the total set of parallel universes make up what is called the 'multiverse', of which one estimate indicates that at most there could be the following number of parallel universes: [2]

$10^{10^{16}} \,$ = number of parallel universes

which multiplied by the number of estimated atoms in our observable universe, indicates that there could be the following number of atoms in the multiverse:

$10^{81} \cdot 10^{10^{16}} \,$

$10^{10^{18}} \,$= number of atoms in the multiverse (hypothetical)

Human molecule
In the English textual context, one would say that one person or one human molecule is comprised of an octillion atoms, of twenty-six types of 'active' elements.

References
1. Thims, Libb. (2008). The Human Molecule (preview) (Google Books). Morrisville, NC: LuLu.
2. Zyga, Lisa. (2009). “Physicists Calculate the Number of Parallel Universes”, Physorg.com, Oct. 16.