809621 has 4 divisors (see below), whose sum is σ = 814752. Its totient is φ = 804492.

The previous prime is 809603. The next prime is 809629. The reversal of 809621 is 126908.

809621 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 809621 - 2¹⁰ = 808597 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (809629) 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, 2321 + ... + 2646.

It is an arithmetic number, because the mean of its divisors is an integer number (203688).

2⁸⁰⁹⁶²¹ is an apocalyptic number.

It is an amenable number.

809621 is a deficient number, since it is larger than the sum of its proper divisors (5131).

809621 is a wasteful number, since it uses less digits than its factorization.

809621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5130.

The product of its (nonzero) digits is 864, while the sum is 26.

The square root of 809621 is about 899.7894198089. The cubic root of 809621 is about 93.2024341312.

The spelling of 809621 in words is "eight hundred nine thousand, six hundred twenty-one".