(number theory) Any natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers.

(grammar) A word that expresses the relative position of an item in a sequence. / (arithmetic) A natural number used to denote position in a sequence.

A number used to denote quantity; a counting number; a cardinal. / (mathematics) A generalized kind of number used to denote the size of a set, including infinite sets.

(number theory) A number that is less than the sum of its proper divisors (all divisors except the number itself).

(mathematics) A number that can be expressed as the ratio of two integers.

(physics, chemistry) The number of protons in an atom. Symbol: Z

(mathematics) The set of positive integers, {1, 2, 3, ...}. / (mathematics, computer science) The set of non-negative integers, {0, 1, 2, 3, ...}.

(mathematics) a positive integer {1, 2, 3, ...} / (mathematics) a non-negative integer {0, 1, 2, ...}

plural of rational number

(mathematics) The set of numbers that can be expressed as a ratio of integers, often denoted with the bold letter Q, or the blackboard bold letter ℚ.