(mathematics) Any number in a Fibonacci sequence (being the sum of the preceding two numbers)

(mathematics) A number that represents the number of items in a pyramid having a given number of sides and layers

(physics) A quantum number related to the difference between the number of leptons and antileptons in a system

(physics) The number of neutrons in the nucleus of an atom or isotope. Symbol: N

plural of number-cruncher (alternative spelling of number cruncher).

plural of number cruncher

An accountant or other person who deals with the calculation of numbers as a profession. / (computing) A program, algorithm, or hardware with a focus on numerical calculation.

(mathematics) Any of the large semiprime numbers to be factored in the RSA Factoring Challenge, a competition from 1991 to 2007 encouraging research into computational number theory.

plural of RSA number

(UK, New Zealand) A telephone number beginning with 0800; these numbers are free for the caller because the call is paid for by the company or organisation being called.