809399205 has 12 divisors (see below), whose sum is σ = 1402958700. Its totient is φ = 431679552.

The previous prime is 809399167. The next prime is 809399209. The reversal of 809399205 is 502993908.

It can be written as a sum of positive squares in 2 ways, for example, as 320016321 + 489382884 = 17889^2 + 22122^2 .

It is not a de Polignac number, because 809399205 - 2¹¹ = 809397157 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45), and also a Moran number because the ratio is a prime number: 17986649 = 809399205 / (8 + 0 + 9 + 3 + 9 + 9 + 2 + 0 + 5).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809399209) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8993280 + ... + 8993369.

It is an arithmetic number, because the mean of its divisors is an integer number (116913225).

Almost surely, 2^809399205 is an apocalyptic number.

It is an amenable number.

809399205 is a deficient number, since it is larger than the sum of its proper divisors (593559495).

809399205 is a wasteful number, since it uses less digits than its factorization.

809399205 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17986660 (or 17986657 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 45.

The square root of 809399205 is about 28449.9420913295. The cubic root of 809399205 is about 931.9392244411.

The spelling of 809399205 in words is "eight hundred nine million, three hundred ninety-nine thousand, two hundred five".