21131112204 has 72 divisors (see below), whose sum is σ = 54834736320. Its totient is φ = 6858012672.

The previous prime is 21131112193. The next prime is 21131112227. The reversal of 21131112204 is 40221113112.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 294202 + ... + 358910.

It is an arithmetic number, because the mean of its divisors is an integer number (761593560).

Almost surely, 2^21131112204 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21131112204, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27417368160).

21131112204 is an abundant number, since it is smaller than the sum of its proper divisors (33703624116).

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

21131112204 is a wasteful number, since it uses less digits than its factorization.

21131112204 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64959 (or 64954 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

Adding to 21131112204 its reverse (40221113112), we get a palindrome (61352225316).

The spelling of 21131112204 in words is "twenty-one billion, one hundred thirty-one million, one hundred twelve thousand, two hundred four".