820121028 has 48 divisors (see below), whose sum is σ = 2003527680. Its totient is φ = 260609184.

The previous prime is 820121011. The next prime is 820121059.

820121028 is nontrivially palindromic in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 820120989 and 820121007.

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, 79893 + ... + 89571.

It is an arithmetic number, because the mean of its divisors is an integer number (41740160).

Almost surely, 2^820121028 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 820121028, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1001763840).

820121028 is an abundant number, since it is smaller than the sum of its proper divisors (1183406652).

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

820121028 is a wasteful number, since it uses less digits than its factorization.

820121028 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10016 (or 10014 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 24.

The square root of 820121028 is about 28637.7552891284. The cubic root of 820121028 is about 936.0362092428.

The spelling of 820121028 in words is "eight hundred twenty million, one hundred twenty-one thousand, twenty-eight".