21500550552 has 128 divisors (see below), whose sum is σ = 59696017920. Its totient is φ = 6410880000.

The previous prime is 21500550541. The next prime is 21500550559. The reversal of 21500550552 is 25505500512.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21500550559) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 1926027 + ... + 1937157.

It is an arithmetic number, because the mean of its divisors is an integer number (466375140).

Almost surely, 2^21500550552 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 21500550552, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29848008960).

21500550552 is an abundant number, since it is smaller than the sum of its proper divisors (38195467368).

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

21500550552 is a wasteful number, since it uses less digits than its factorization.

21500550552 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11345 (or 11341 counting only the distinct ones).

The product of its (nonzero) digits is 12500, while the sum is 30.

The spelling of 21500550552 in words is "twenty-one billion, five hundred million, five hundred fifty thousand, five hundred fifty-two".