821221122128 has 40 divisors (see below), whose sum is σ = 1739628835200. Its totient is φ = 372450928640.

The previous prime is 821221122119. The next prime is 821221122181.

821221122128 is nontrivially palindromic in base 10.

821221122128 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a nude number because it is divisible by every one of its digits.

It is a junction number, because it is equal to n+sod(n) for n = 821221122094 and 821221122103.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5117000 + ... + 5275047.

It is an arithmetic number, because the mean of its divisors is an integer number (43490720880).

Almost surely, 2^821221122128 is an apocalyptic number.

821221122128 is a gapful number since it is divisible by the number (88) formed by its first and last digit.

It is an amenable number.

821221122128 is an abundant number, since it is smaller than the sum of its proper divisors (918407713072).

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

821221122128 is a wasteful number, since it uses less digits than its factorization.

821221122128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10392515 (or 10392509 counting only the distinct ones).

The product of its digits is 4096, while the sum is 32.

It can be divided in two parts, 821221 and 122128, that added together give a palindrome (943349).

The spelling of 821221122128 in words is "eight hundred twenty-one billion, two hundred twenty-one million, one hundred twenty-two thousand, one hundred twenty-eight".