821222128 has 80 divisors (see below), whose sum is σ = 1738951200. Its totient is φ = 374169600.

The previous prime is 821222119. The next prime is 821222183.

821222128 is nontrivially palindromic in base 10.

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 = 821222096 and 821222105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2352898 + ... + 2353246.

It is an arithmetic number, because the mean of its divisors is an integer number (21736890).

Almost surely, 2^821222128 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 821222128, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (869475600).

821222128 is an abundant number, since it is smaller than the sum of its proper divisors (917729072).

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

821222128 is a wasteful number, since it uses less digits than its factorization.

821222128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 626 (or 620 counting only the distinct ones).

The product of its digits is 2048, while the sum is 28.

The square root of 821222128 is about 28656.9734619691. The cubic root of 821222128 is about 936.4549314059.

The spelling of 821222128 in words is "eight hundred twenty-one million, two hundred twenty-two thousand, one hundred twenty-eight".