21020204044 has 72 divisors (see below), whose sum is σ = 43229204928. Its totient is φ = 8916929280.

The previous prime is 21020204033. The next prime is 21020204059. The reversal of 21020204044 is 44040202012.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8264637 + ... + 8267179.

It is an arithmetic number, because the mean of its divisors is an integer number (600405624).

Almost surely, 2^21020204044 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 21020204044, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21614602464).

21020204044 is an abundant number, since it is smaller than the sum of its proper divisors (22209000884).

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

21020204044 is a wasteful number, since it uses less digits than its factorization.

21020204044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2975 (or 2966 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 19.

Adding to 21020204044 its reverse (44040202012), we get a palindrome (65060406056).

The spelling of 21020204044 in words is "twenty-one billion, twenty million, two hundred four thousand, forty-four".