Thirty

The thirty (30) is the natural number that follows twenty-nine and precedes thirty-one.

Mathematical properties

• 30 is a composite number, which has the following factors: 1, 2, 3, 5, 6, 10 and 15. As the sum of its factors is 42 /2005 30, it is an abundant number.
• Thirty is a cousin because it is the product of the first three prime numbers: 30 = 2 · 3 · 5. It is also a spherical number, a number of Harshad, the smaller number of Giuga and the fourth square pyramidal number.
• A thirty-sided polygon is called Triacontágono'.
• The icosaedro and the dodecaedro are platonic solids with 30 edges.
• It's a Harshad number.
• It's a semi-perfect number.
• Free number of squares.