21115503245555 has 32 divisors (see below), whose sum is σ = 25462738312704. Its totient is φ = 16809850688256.

The previous prime is 21115503245549. The next prime is 21115503245591. The reversal of 21115503245555 is 55554230551112.

It is a cyclic number.

It is not a de Polignac number, because 21115503245555 - 2⁶ = 21115503245491 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3023840594 + ... + 3023847576.

It is an arithmetic number, because the mean of its divisors is an integer number (795710572272).

Almost surely, 2^{21115503245555} is an apocalyptic number.

21115503245555 is a deficient number, since it is larger than the sum of its proper divisors (4347235067149).

21115503245555 is a wasteful number, since it uses less digits than its factorization.

21115503245555 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10235.

The product of its (nonzero) digits is 750000, while the sum is 44.

Adding to 21115503245555 its reverse (55554230551112), we get a palindrome (76669733796667).

The spelling of 21115503245555 in words is "twenty-one trillion, one hundred fifteen billion, five hundred three million, two hundred forty-five thousand, five hundred fifty-five".