821404206 has 64 divisors (see below), whose sum is σ = 2092262400. Its totient is φ = 233994528.

The previous prime is 821404201. The next prime is 821404217. The reversal of 821404206 is 602404128.

821404206 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a self number, because there is not a number n which added to its sum of digits gives 821404206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821404201) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 132676 + ... + 138728.

It is an arithmetic number, because the mean of its divisors is an integer number (32691600).

Almost surely, 2^821404206 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821404206, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1046131200).

821404206 is an abundant number, since it is smaller than the sum of its proper divisors (1270858194).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

821404206 is a wasteful number, since it uses less digits than its factorization.

821404206 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6430 (or 6424 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 27.

The square root of 821404206 is about 28660.1501391741. The cubic root of 821404206 is about 936.5241352730.

The spelling of 821404206 in words is "eight hundred twenty-one million, four hundred four thousand, two hundred six".