21216198528 has 192 divisors, whose sum is σ = 69942787200. Its totient is φ = 6047069184.

The previous prime is 21216198491. The next prime is 21216198529. The reversal of 21216198528 is 82589161212.

21216198528 is a `hidden beast` number, since 2 + 1 + 2 + 1 + 619 + 8 + 5 + 28 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21216198529) by changing a digit.

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, 3569383 + ... + 3575321.

It is an arithmetic number, because the mean of its divisors is an integer number (364285350).

Almost surely, 2^21216198528 is an apocalyptic number.

21216198528 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21216198528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34971393600).

21216198528 is an abundant number, since it is smaller than the sum of its proper divisors (48726588672).

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

21216198528 is a wasteful number, since it uses less digits than its factorization.

21216198528 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6409 (or 6394 counting only the distinct ones).

The product of its digits is 138240, while the sum is 45.

The spelling of 21216198528 in words is "twenty-one billion, two hundred sixteen million, one hundred ninety-eight thousand, five hundred twenty-eight".