990309 has 4 divisors (see below), whose sum is σ = 1320416. Its totient is φ = 660204.

The previous prime is 990307. The next prime is 990313. The reversal of 990309 is 903099.

990309 = 226² + 227² + ... + 243².

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 990309 - 2¹ = 990307 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 990309.

It is not an unprimeable number, because it can be changed into a prime (990307) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 165049 + ... + 165054.

It is an arithmetic number, because the mean of its divisors is an integer number (330104).

2⁹⁹⁰³⁰⁹ is an apocalyptic number.

It is an amenable number.

990309 is a deficient number, since it is larger than the sum of its proper divisors (330107).

990309 is a wasteful number, since it uses less digits than its factorization.

990309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 330106.

The product of its (nonzero) digits is 2187, while the sum is 30.

The square root of 990309 is about 995.1427033346. The cubic root of 990309 is about 99.6759175066.

The spelling of 990309 in words is "nine hundred ninety thousand, three hundred nine".