805721 has 16 divisors (see below), whose sum is σ = 983040. Its totient is φ = 645840.

The previous prime is 805711. The next prime is 805723. The reversal of 805721 is 127508.

805721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 805721 - 2¹⁰ = 804697 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (805723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10160 + ... + 10238.

It is an arithmetic number, because the mean of its divisors is an integer number (61440).

2⁸⁰⁵⁷²¹ is an apocalyptic number.

It is an amenable number.

805721 is a deficient number, since it is larger than the sum of its proper divisors (177319).

805721 is a wasteful number, since it uses less digits than its factorization.

805721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 164.

The product of its (nonzero) digits is 560, while the sum is 23.

The square root of 805721 is about 897.6196299101. The cubic root of 805721 is about 93.0525390110.

The spelling of 805721 in words is "eight hundred five thousand, seven hundred twenty-one".