809084021 has 4 divisors (see below), whose sum is σ = 836983500. Its totient is φ = 781184544.

The previous prime is 809083999. The next prime is 809084099. The reversal of 809084021 is 120480908.

It is a happy number.

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 610584100 + 198499921 = 24710^2 + 14089^2 .

It is a cyclic number.

It is not a de Polignac number, because 809084021 - 2¹⁰ = 809082997 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809084921) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 13949696 + ... + 13949753.

It is an arithmetic number, because the mean of its divisors is an integer number (209245875).

Almost surely, 2^809084021 is an apocalyptic number.

It is an amenable number.

809084021 is a deficient number, since it is larger than the sum of its proper divisors (27899479).

809084021 is a wasteful number, since it uses less digits than its factorization.

809084021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27899478.

The product of its (nonzero) digits is 4608, while the sum is 32.

The square root of 809084021 is about 28444.4022788316. The cubic root of 809084021 is about 931.8182415088.

The spelling of 809084021 in words is "eight hundred nine million, eighty-four thousand, twenty-one".