What is a number that can be expressed using an exponent?

Any number can be expressed using an exponent, although most commonly, very large and very small numbers are expressed with exponents. These numbers are written in scientific notation or exponential notation.

Writing large or small numbers in standard exponential notation, or scientific notation, provides a shorthand method to write out numbers with a large number of trailing zeros or leading zero decimal places. Most commonly, numbers are written in exponential notation using the form: [number] * 10^[power], where the number to the left of the exponent is between 1 and less than 10, and the power is an integer. For example, the number 50,150,000,000,000,000,000,000 can be expressed as 5.015 * 10^22.