806544021 has 4 divisors (see below), whose sum is σ = 1075392032. Its totient is φ = 537696012.

The previous prime is 806543987. The next prime is 806544023. The reversal of 806544021 is 120445608.

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 not a de Polignac number, because 806544021 - 2⁷ = 806543893 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 806544021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (806544023) 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, 134424001 + ... + 134424006.

It is an arithmetic number, because the mean of its divisors is an integer number (268848008).

Almost surely, 2^806544021 is an apocalyptic number.

It is an amenable number.

806544021 is a deficient number, since it is larger than the sum of its proper divisors (268848011).

806544021 is a wasteful number, since it uses less digits than its factorization.

806544021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 268848010.

The product of its (nonzero) digits is 7680, while the sum is 30.

The square root of 806544021 is about 28399.7186781841. The cubic root of 806544021 is about 930.8421173322.

Adding to 806544021 its reverse (120445608), we get a palindrome (926989629).

The spelling of 806544021 in words is "eight hundred six million, five hundred forty-four thousand, twenty-one".