21204347955 has 48 divisors (see below), whose sum is σ = 39483845280. Its totient is φ = 9689046528.

The previous prime is 21204347951. The next prime is 21204347963. The reversal of 21204347955 is 55974340212.

It is a happy number.

It is not a de Polignac number, because 21204347955 - 2² = 21204347951 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21204347951) 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 47 ways as a sum of consecutive naturals, for example, 2080111 + ... + 2090279.

It is an arithmetic number, because the mean of its divisors is an integer number (822580110).

Almost surely, 2^21204347955 is an apocalyptic number.

21204347955 is a deficient number, since it is larger than the sum of its proper divisors (18279497325).

21204347955 is a wasteful number, since it uses less digits than its factorization.

21204347955 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13028 (or 13021 counting only the distinct ones).

The product of its (nonzero) digits is 302400, while the sum is 42.

The spelling of 21204347955 in words is "twenty-one billion, two hundred four million, three hundred forty-seven thousand, nine hundred fifty-five".