990990 has 144 divisors (see below), whose sum is σ = 3485664. Its totient is φ = 190080.

The previous prime is 990989. The next prime is 991009. The reversal of 990990 is 99099.

It is a super-2 number, since 2×990990² = 1964122360200, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 76224 + ... + 76236.

It is an arithmetic number, because the mean of its divisors is an integer number (24206).

2⁹⁹⁰⁹⁹⁰ is an apocalyptic number.

990990 is a gapful number since it is divisible by the number (90) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 990990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1742832).

990990 is an abundant number, since it is smaller than the sum of its proper divisors (2494674).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

990990 is a wasteful number, since it uses less digits than its factorization.

990990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 55 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 6561, while the sum is 36.

The square root of 990990 is about 995.4848065139. The cubic root of 990990 is about 99.6987601232.

It can be divided in two parts, 9909 and 90, that added together give a palindrome (9999).

The spelling of 990990 in words is "nine hundred ninety thousand, nine hundred ninety".