Eighty-four

The eighty-four (84) is the natural number that follows eighty-three and precedes eighty-five.

Mathematical properties

• It is a composite number, which has the following factors: 1, 2, 3, 4, 6, 7, 12, 14, 21, 28 and 42. As the sum of its factors is 140 /2005 84, it is an abundant number.
• It is the sum of the first seven triangular numbers, which makes it a tetraetric number.
• It's a Harshad number and a Moran number.

Features

• 84 is the atomic number of the polonium.