990

990 is the natural number that follows 989 and precedes 991. It is an even composite number with prime factorization 2 × 3^2 × 5 × 11. Its divisors include 1, 2, 3, 5, 6, 9, 10, 11, 15, 18, 22, 30, 33, 45, 55, 66, 90, 99, 110, 165, 198, 330, 495, and 990. The sum of its proper divisors is 1818, which makes 990 an abundant number. It is also a Harshad number, since it is divisible by the sum of its digits (9 + 9 + 0 = 18).

In Roman numerals, 990 is written as CMXC.

In public administration and nonprofit contexts, Form 990 refers to a set of annual information returns filed with the United States Internal Revenue Service by most organizations exempt from federal income tax. The standard form is Form 990; smaller organizations may file Form 990-EZ or Form 990-N, and private foundations file Form 990-PF. These forms disclose revenue, expenses, governance, compensation, and program descriptions, and they are intended to provide transparency to the public. Filing requirements depend on organizational size and type, and the information reported is used by the IRS and the public to assess compliance and program impact.

Beyond mathematics and tax, 990 may appear in other contexts as a model or product number, or as a year reference in historical timelines.