990009 has 16 divisors (see below), whose sum is σ = 1507840. Its totient is φ = 641520.

The previous prime is 990001. The next prime is 990013. The reversal of 990009 is 900099.

It is not a de Polignac number, because 990009 - 2³ = 990001 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (990001) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 504 + ... + 1494.

It is an arithmetic number, because the mean of its divisors is an integer number (94240).

2⁹⁹⁰⁰⁰⁹ is an apocalyptic number.

It is an amenable number.

990009 is a deficient number, since it is larger than the sum of its proper divisors (517831).

990009 is a wasteful number, since it uses less digits than its factorization.

990009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1037 (or 1031 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 27.

The square root of 990009 is about 994.9919597665. The cubic root of 990009 is about 99.6658513572.

The spelling of 990009 in words is "nine hundred ninety thousand, nine".