Twenty-four is a composite number with proper divisors 1, 2, 3, 4, 6, 8 and 12.

Also:

• 24 is the factorial of 4 (4! = 24)
• 24 is a nonagonal number
• The product of any four consecutive numbers is divisible by 24. This is because among any four consecutive numbers there must be two even numbers, one of which is a multiple of 4, and there must be at least one multiple of 3
• A truncated cube, a truncated octahedron, a rhombicuboctahedron, a snub cube, a small cubicuboctahedron, a great cubicuboctahedron, a quasirhombicuboctahedron, a small rhombihexahedron, a quasitruncated hexahedron, and a great rhombihexahedron have 24 vertices
• A cuboctahedron, a octahemioctahedron, and a cubohemioctahedron have 24 edges
• A dodecadodecahedron, a truncated great dodecahedron, a ditrigonal dodecahedron, and a quasitruncated small stellated dodecahedron have 24 faces
• A great snub dodecicosidodecahedron and a great dirhombicosidodecahedron have 24 pentagrams.