21204232055 has 4 divisors (see below), whose sum is σ = 25445078472. Its totient is φ = 16963385640.

The previous prime is 21204232043. The next prime is 21204232099. The reversal of 21204232055 is 55023240212.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 21204232055 - 2⁸ = 21204231799 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2120423201 + ... + 2120423210.

It is an arithmetic number, because the mean of its divisors is an integer number (6361269618).

Almost surely, 2^21204232055 is an apocalyptic number.

21204232055 is a deficient number, since it is larger than the sum of its proper divisors (4240846417).

21204232055 is an equidigital number, since it uses as much as digits as its factorization.

21204232055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4240846416.

The product of its (nonzero) digits is 4800, while the sum is 26.

Adding to 21204232055 its reverse (55023240212), we get a palindrome (76227472267).

The spelling of 21204232055 in words is "twenty-one billion, two hundred four million, two hundred thirty-two thousand, fifty-five".