809791 has 4 divisors (see below), whose sum is σ = 829584. Its totient is φ = 790000.

The previous prime is 809779. The next prime is 809797. The reversal of 809791 is 197908.

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

It is a cyclic number.

It is not a de Polignac number, because 809791 - 2⁵ = 809759 is a prime.

It is a super-2 number, since 2×809791² = 1311522927362, which contains 22 as substring.

It is a Duffinian number.

It is a plaindrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809797) 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, 9835 + ... + 9916.

It is an arithmetic number, because the mean of its divisors is an integer number (207396).

2⁸⁰⁹⁷⁹¹ is an apocalyptic number.

809791 is a deficient number, since it is larger than the sum of its proper divisors (19793).

809791 is a wasteful number, since it uses less digits than its factorization.

809791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19792.

The product of its (nonzero) digits is 4536, while the sum is 34.

The square root of 809791 is about 899.8838813980. The cubic root of 809791 is about 93.2089570619.

It can be divided in two parts, 809 and 791, that added together give a square (1600 = 40²).

The spelling of 809791 in words is "eight hundred nine thousand, seven hundred ninety-one".