21103356500 has 48 divisors (see below), whose sum is σ = 46171354320. Its totient is φ = 8426393600.

The previous prime is 21103356499. The next prime is 21103356509. The reversal of 21103356500 is 565330112.

It can be written as a sum of positive squares in 8 ways, for example, as 12055161616 + 9048194884 = 109796^2 + 95122^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21103356500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21103356509) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 247412 + ... + 321588.

It is an arithmetic number, because the mean of its divisors is an integer number (961903215).

Almost surely, 2^21103356500 is an apocalyptic number.

21103356500 is a gapful number since it is divisible by the number (20) 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 21103356500, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23085677160).

21103356500 is an abundant number, since it is smaller than the sum of its proper divisors (25067997820).

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

21103356500 is a wasteful number, since it uses less digits than its factorization.

21103356500 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74765 (or 74753 counting only the distinct ones).

The product of its (nonzero) digits is 2700, while the sum is 26.

Adding to 21103356500 its reverse (565330112), we get a palindrome (21668686612).

The spelling of 21103356500 in words is "twenty-one billion, one hundred three million, three hundred fifty-six thousand, five hundred".