999903209 has 16 divisors (see below), whose sum is σ = 1060984320. Its totient is φ = 940705920.

The previous prime is 999903167. The next prime is 999903217. The reversal of 999903209 is 902309999.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-999903209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (999903259) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 756269 + ... + 757589.

It is an arithmetic number, because the mean of its divisors is an integer number (66311520).

Almost surely, 2^999903209 is an apocalyptic number.

It is an amenable number.

999903209 is a deficient number, since it is larger than the sum of its proper divisors (61081111).

999903209 is a wasteful number, since it uses less digits than its factorization.

999903209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2000.

The product of its (nonzero) digits is 354294, while the sum is 50.

The square root of 999903209 is about 31621.2461645647. The cubic root of 999903209 is about 999.9677352923.

The spelling of 999903209 in words is "nine hundred ninety-nine million, nine hundred three thousand, two hundred nine".