809712205 has 4 divisors (see below), whose sum is σ = 971654652. Its totient is φ = 647769760.

The previous prime is 809712203. The next prime is 809712223. The reversal of 809712205 is 502217908.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 311663716 + 498048489 = 17654^2 + 22317^2 .

It is not a de Polignac number, because 809712205 - 2¹ = 809712203 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809712203) 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 3 ways as a sum of consecutive naturals, for example, 80971216 + ... + 80971225.

It is an arithmetic number, because the mean of its divisors is an integer number (242913663).

Almost surely, 2^809712205 is an apocalyptic number.

It is an amenable number.

809712205 is a deficient number, since it is larger than the sum of its proper divisors (161942447).

809712205 is a wasteful number, since it uses less digits than its factorization.

809712205 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161942446.

The product of its (nonzero) digits is 10080, while the sum is 34.

The square root of 809712205 is about 28455.4424495561. The cubic root of 809712205 is about 932.0593379702.

It can be divided in two parts, 8097 and 12205, that added together give a palindrome (20302).

The spelling of 809712205 in words is "eight hundred nine million, seven hundred twelve thousand, two hundred five".