809209421 has 4 divisors (see below), whose sum is σ = 813276000. Its totient is φ = 805142844.

The previous prime is 809209409. The next prime is 809209439. The reversal of 809209421 is 124902908.

809209421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 809209421 - 2¹⁰ = 809208397 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 (809209441) 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, 2032991 + ... + 2033388.

It is an arithmetic number, because the mean of its divisors is an integer number (203319000).

Almost surely, 2^809209421 is an apocalyptic number.

It is an amenable number.

809209421 is a deficient number, since it is larger than the sum of its proper divisors (4066579).

809209421 is a wasteful number, since it uses less digits than its factorization.

809209421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4066578.

The product of its (nonzero) digits is 10368, while the sum is 35.

The square root of 809209421 is about 28446.6064935697. The cubic root of 809209421 is about 931.8663798842.

The spelling of 809209421 in words is "eight hundred nine million, two hundred nine thousand, four hundred twenty-one".