822128821 has 4 divisors (see below), whose sum is σ = 822254112. Its totient is φ = 822003532.

The previous prime is 822128779. The next prime is 822128849. The reversal of 822128821 is 128821228.

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 a de Polignac number, because none of the positive numbers 2^k-822128821 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (822123821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 52225 + ... + 66118.

It is an arithmetic number, because the mean of its divisors is an integer number (205563528).

Almost surely, 2^822128821 is an apocalyptic number.

It is an amenable number.

822128821 is a deficient number, since it is larger than the sum of its proper divisors (125291).

822128821 is a wasteful number, since it uses less digits than its factorization.

822128821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125290.

The product of its digits is 8192, while the sum is 34.

The square root of 822128821 is about 28672.7888598232. The cubic root of 822128821 is about 936.7994443017.

The spelling of 822128821 in words is "eight hundred twenty-two million, one hundred twenty-eight thousand, eight hundred twenty-one".