809730661 has 4 divisors (see below), whose sum is σ = 825008652. Its totient is φ = 794452672.

The previous prime is 809730659. The next prime is 809730667. The reversal of 809730661 is 166037908.

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 470065761 + 339664900 = 21681^2 + 18430^2 .

It is a cyclic number.

It is not a de Polignac number, because 809730661 - 2¹ = 809730659 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 (809730667) 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, 7638916 + ... + 7639021.

It is an arithmetic number, because the mean of its divisors is an integer number (206252163).

Almost surely, 2^809730661 is an apocalyptic number.

It is an amenable number.

809730661 is a deficient number, since it is larger than the sum of its proper divisors (15277991).

809730661 is a wasteful number, since it uses less digits than its factorization.

809730661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15277990.

The product of its (nonzero) digits is 54432, while the sum is 40.

The square root of 809730661 is about 28455.7667441944. The cubic root of 809730661 is about 932.0664194807.

The spelling of 809730661 in words is "eight hundred nine million, seven hundred thirty thousand, six hundred sixty-one".