plural of Wratten number

Any of the arbitrary alphanumeric codes in a system for labelling optical filters, usually for photographic use.

plural of silent number

plural of call number

plural of dial number

plural of Bernoulli number

The property of being a number.

(mathematics) A positive integer that cannot be expressed as the sum of all the proper divisors of any positive integer (including the untouchable number itself).

plural of untouchable number

plural of oxidation number