There are 11 solutions to the equation φ(x) = 48, namely 65, 104, 105, 112, 130, 140, 144, 156, 168, 180 and 210. This is more than any integer below 48, making 48 a highly totient number.

[edit]

In science

The atomic number of cadmium
The number of Ptolemaic constellations

In astronomy,

Messier object M48, a magnitude 5.5 open cluster in the constellation Hydra

The New General Catalogue object (http://www.ngcic.org/) NGC 48, a barred spiral galaxy in the constellation Andromeda

The Saros number (http://sunearth.gsfc.nasa.gov/eclipse/SEsaros/SEsaros1-175.html) of the solar eclipse series which began on -1331 February 8 and ended on -15 April 9. The duration of Saros series 48 was 1316.2 years, and it contained 74 solar eclipses.

The Saros number (http://sunearth.gsfc.nasa.gov/eclipse/LEsaros/LEsaros1-175.html) of the lunar eclipse series which began on -1246 July 11 and ended on 124 October 11. The duration of Saros series 48 was 1370.3 years, and it contained 77 lunar eclipses.

[edit]

In other fields

Forty-eight is also:

twice the total number of major and minor keys in the Western tonal music (twenty-four), not counting enharmonic equivalents. Johann Sebastian Bach's Well-Tempered Clavier is informally known as The Forty-Eight because it consists of a prelude and a fugue in each major and minor key, for a total of forty-eight pieces.
the code for international direct dial phone calls to Poland.
the model number of the HP-48 S/SX/G/GX/G+/GII
the number of hours in two days, and hence also part of the title of the movies 48 Hrs. and Another 48 Hrs., starring Eddie Murphy and Nick Nolte.
the years AD 48, 48 BC, or 1948.es:Cuarenta y ocho