805921 has 4 divisors (see below), whose sum is σ = 817344. Its totient is φ = 794500.

The previous prime is 805913. The next prime is 805933. The reversal of 805921 is 129508.

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 805921 - 2³ = 805913 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (805901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5605 + ... + 5746.

It is an arithmetic number, because the mean of its divisors is an integer number (204336).

2⁸⁰⁵⁹²¹ is an apocalyptic number.

It is an amenable number.

805921 is a deficient number, since it is larger than the sum of its proper divisors (11423).

805921 is a wasteful number, since it uses less digits than its factorization.

805921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11422.

The product of its (nonzero) digits is 720, while the sum is 25.

The square root of 805921 is about 897.7310287608. The cubic root of 805921 is about 93.0602376925.

The spelling of 805921 in words is "eight hundred five thousand, nine hundred twenty-one".