21204440012 has 12 divisors (see below), whose sum is σ = 42408880080. Its totient is φ = 9087617136.

The previous prime is 21204440011. The next prime is 21204440027. The reversal of 21204440012 is 21004440212.

21204440012 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (21204440011) 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 3 ways as a sum of consecutive naturals, for example, 378650687 + ... + 378650742.

It is an arithmetic number, because the mean of its divisors is an integer number (3534073340).

Almost surely, 2^21204440012 is an apocalyptic number.

It is an amenable number.

21204440012 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21204440012 is a wasteful number, since it uses less digits than its factorization.

21204440012 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 757301440 (or 757301438 counting only the distinct ones).

The product of its (nonzero) digits is 512, while the sum is 20.

Adding to 21204440012 its reverse (21004440212), we get a palindrome (42208880224).

The spelling of 21204440012 in words is "twenty-one billion, two hundred four million, four hundred forty thousand, twelve".