821220121022128 has 20 divisors (see below), whose sum is σ = 1660292853371568. Its totient is φ = 392757449184320.

The previous prime is 821220121022123. The next prime is 821220121022131.

821220121022128 is nontrivially palindromic in base 10.

821220121022128 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 821220121022093 and 821220121022102.

It is not an unprimeable number, because it can be changed into a prime (821220121022123) 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, 1115788207543 + ... + 1115788208278.

Almost surely, 2^{821220121022128} is an apocalyptic number.

It is an amenable number.

821220121022128 is an abundant number, since it is smaller than the sum of its proper divisors (839072732349440).

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

821220121022128 is a wasteful number, since it uses less digits than its factorization.

821220121022128 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2231576415852 (or 2231576415846 counting only the distinct ones).

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

The spelling of 821220121022128 in words is "eight hundred twenty-one trillion, two hundred twenty billion, one hundred twenty-one million, twenty-two thousand, one hundred twenty-eight".