48 (number) facts for kids

48 (forty-eight) is the natural number following 47 and preceding 49. It is one third of a gross, or four dozens.

48 hours equals 2 days.

In mathematics

Forty-eight is the double factorial of 6, a highly composite number. Like all other multiples of 6, it is a semiperfect number. 48 is the second 17-gonal number.

48 is the smallest number with exactly ten divisors.

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.

Since the greatest prime factor of 48² + 1 = 2305 is 461, which is clearly more than twice 48, 48 is a Størmer number.

48 is a Harshad number in base 10. It has 24, 2, 12, and 4 as factors.

In science

• The atomic number of cadmium.
• The number of Ptolemaic constellations.
• The number of symmetries of a cube.

Astronomy

• Messier object M48, a magnitude 5.5 open cluster in the constellation Hydra.
• The New General Catalogue object NGC 48, a barred spiral galaxy in the constellation Andromeda.

In religion

• The prophecies of 48 Jewish prophets and 7 prophetesses were recorded in the Tanakh for posterity.
• According to the Mishnah, Torah wisdom is acquired via 48 ways (Pirkei Avoth 6:6).
• In Buddhism, Amitabha Buddha had made 48 great vows and promises to provide ultimate salvation to countless beings through countless eons, with benefits said to be available merely by thinking about his name with Nianfo practice. He is thus hailed as "King of Buddhas" through such skillful compassion and became a popular and formal refuge figure in Pureland Buddhism.

See also

In Spanish: Cuarenta y ocho para niños