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# The number 28 (twenty eight). Interesting and fun facts about 28.

**More non-math facts about the number 28:**

In chemistry, 28 is the atomic number of nickel.

In biology, the average human menstrual cycles is 28 days.

The shortest month of the year with 28 days is February.

In astrophysics, the surface of the sun takes 28 days to rotate.

There are 28 dominoes in a full set of dominoes.

In music, an Australian rock band is called “28 days”. Also “Twenty-Eight Teeth” is a song by Buck-O-Nine.

In the movies, “28 Days” is an American movies made in 2000 starring Sandra Bullock. There is also a British made horror film call “28 Days Later”.

**Here are some math facts about the number 28:**

The number 28 is the fourteenth even number as is a multiple of 2.

The number 28 has six distinct factors. These are 1,2,4,7,14 and 28.

It is also recognised as a perfect number as if you sum up all the factors (excluding 28) you get a total of 28 (1+2+4+7+14=28).

The prime factor decomposition of 28 is 2 x 2 x 7.

The square of 28 is 784. Also if you square root 28 you get 5.29 rounded to 3 significant figures.

28% as a decimal is 0.28 and as fraction is 7/25.

The cube of twenty eight is 21952.

In the binary number system 28 can be written as 11100.

In the hexadecimal number system 28 can be written as 1C.

In Roman Numerals the number 28 can be written as XXVIII

**Popular conversions involving the number 28:**

A length of 28 miles is the same as 45.1 kilometers. Also, a speed of 28mph is 45.1kmph.

A length of 28 feet is the same as 8.53 meters.

A time of 28 hours is the same as 100800 seconds.

A weight of 28 pounds is the same as 12.7 kilograms.