809971 has 4 divisors (see below), whose sum is σ = 813600. Its totient is φ = 806344.

The previous prime is 809929. The next prime is 809981. The reversal of 809971 is 179908.

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 809971 - 2⁷ = 809843 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (809981) 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, 1456 + ... + 1933.

It is an arithmetic number, because the mean of its divisors is an integer number (203400).

2⁸⁰⁹⁹⁷¹ is an apocalyptic number.

809971 is a deficient number, since it is larger than the sum of its proper divisors (3629).

809971 is a wasteful number, since it uses less digits than its factorization.

809971 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3628.

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

The square root of 809971 is about 899.9838887447. The cubic root of 809971 is about 93.2158626994.

The spelling of 809971 in words is "eight hundred nine thousand, nine hundred seventy-one".