(mathematics) Any element of a field equivalent to the real numbers augmented with infinite and infinitesimal numbers (respectively larger and smaller (in absolute value) than any positive real number).

(number theory) Any of a sequence of numbers having the property that the sum of the divisors of each, excluding itself, is equal to the next number in the sequence; in the case of the last number of the sequence, the sum of the divisors, excluding that number, is equal to the first number of the sequence.

plural of sociable number

plural of hyperreal number

A dimensionless number used in heat transfer calculations, giving a simple index of the ratio of the heat transfer resistances inside of and at the surface of a body.

plural of numbers station

A shortwave radio station characterized by unusual broadcasts, often of artificially generated voices reciting streams of numbers, words, etc., supposed to be coded messages.

Synonym of mass number

Alternative spelling of number-crunching

(mathematics, obsolete) A fraction.