21115503245556 has 72 divisors (see below), whose sum is σ = 53888414580000. Its totient is φ = 6971048735040.

The previous prime is 21115503245549. The next prime is 21115503245591. The reversal of 21115503245556 is 65554230551112.

21115503245556 is a `hidden beast` number, since 2 + 1 + 1 + 1 + 5 + 50 + 3 + 2 + 45 + 556 = 666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1997806 + ... + 6798693.

It is an arithmetic number, because the mean of its divisors is an integer number (748450202500).

Almost surely, 2^{21115503245556} is an apocalyptic number.

It is an amenable number.

21115503245556 is an abundant number, since it is smaller than the sum of its proper divisors (32772911334444).

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

21115503245556 is a wasteful number, since it uses less digits than its factorization.

21115503245556 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8797149 (or 8797144 counting only the distinct ones).

The product of its (nonzero) digits is 900000, while the sum is 45.

Adding to 21115503245556 its reverse (65554230551112), we get a palindrome (86669733796668).

The spelling of 21115503245556 in words is "twenty-one trillion, one hundred fifteen billion, five hundred three million, two hundred forty-five thousand, five hundred fifty-six".