Thirty-three is a composite number: $33=3 \times 11$.

Also:

• 33 is the sum of three cubes: $33=\left(8\,866\,128\,975\,287\,528\right)^3+\left(-8\,778\,405\,442\,862\,239\right)^3+\left(-2\,736\,111\,468\,807\,040\right)^3$