In math and science seven is a prime number, a seven-sided shape is a heptagon, and there are seven types of catastrophes. There are seven colors of the rainbow – red, orange, yellow, green, blue, indigo, and violet. There are seven types of virus. There are seven objects in the solar system visible to the naked eye from Earth – the Sun, the Moon, Mars, Mercury, Jupiter, Venus, and Saturn.
Is Seven a lucky number? Well many people believe it is and Las Vegas is willing to put money on it. Seven is the sum of any two opposite sides on a standard six-sided die. When rolling two standard six-sided dice, seven has a 6 in 36 (or 1/6) probability of being rolled (1–6, 6–1, 2–5, 5–2, 3–4, or 4–3), the greatest chance of occurring than any other number.