813931209 has 108 divisors (see below), whose sum is σ = 1512244656. Its totient is φ = 420323904.

The previous prime is 813931207. The next prime is 813931213. The reversal of 813931209 is 902139318.

It is not a de Polignac number, because 813931209 - 2¹ = 813931207 is a prime.

It is not an unprimeable number, because it can be changed into a prime (813931201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 4993362 + ... + 4993524.

Almost surely, 2^813931209 is an apocalyptic number.

It is an amenable number.

813931209 is a deficient number, since it is larger than the sum of its proper divisors (698313447).

813931209 is a wasteful number, since it uses less digits than its factorization.

813931209 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276 (or 253 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The square root of 813931209 is about 28529.4796482516. The cubic root of 813931209 is about 933.6753656147.

The spelling of 813931209 in words is "eight hundred thirteen million, nine hundred thirty-one thousand, two hundred nine".