21500372432 has 80 divisors (see below), whose sum is σ = 51963638400. Its totient is φ = 8372305920.

The previous prime is 21500372401. The next prime is 21500372449. The reversal of 21500372432 is 23427300512.

It is a junction number, because it is equal to n+sod(n) for n = 21500372395 and 21500372404.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3210944 + ... + 3217632.

It is an arithmetic number, because the mean of its divisors is an integer number (649545480).

Almost surely, 2^21500372432 is an apocalyptic number.

21500372432 is a gapful number since it is divisible by the number (22) 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 21500372432, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25981819200).

21500372432 is an abundant number, since it is smaller than the sum of its proper divisors (30463265968).

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

21500372432 is a wasteful number, since it uses less digits than its factorization.

21500372432 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9324 (or 9318 counting only the distinct ones).

The product of its (nonzero) digits is 10080, while the sum is 29.

Adding to 21500372432 its reverse (23427300512), we get a palindrome (44927672944).

The spelling of 21500372432 in words is "twenty-one billion, five hundred million, three hundred seventy-two thousand, four hundred thirty-two".