821004805 has 16 divisors (see below), whose sum is σ = 1010560320. Its totient is φ = 639975168.

The previous prime is 821004773. The next prime is 821004809. The reversal of 821004805 is 508400128.

It is a cyclic number.

It is not a de Polignac number, because 821004805 - 2⁵ = 821004773 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821004809) 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, 88686 + ... + 97504.

It is an arithmetic number, because the mean of its divisors is an integer number (63160020).

Almost surely, 2^821004805 is an apocalyptic number.

It is an amenable number.

821004805 is a deficient number, since it is larger than the sum of its proper divisors (189555515).

821004805 is a wasteful number, since it uses less digits than its factorization.

821004805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9300.

The product of its (nonzero) digits is 2560, while the sum is 28.

The square root of 821004805 is about 28653.1814114943. The cubic root of 821004805 is about 936.3723182927.

The spelling of 821004805 in words is "eight hundred twenty-one million, four thousand, eight hundred five".