21521334044 has 12 divisors (see below), whose sum is σ = 43042668144. Its totient is φ = 9223428864.

The previous prime is 21521334013. The next prime is 21521334089. The reversal of 21521334044 is 44043312512.

21521334044 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 21521333998 and 21521334016.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 384309509 + ... + 384309564.

It is an arithmetic number, because the mean of its divisors is an integer number (3586889012).

Almost surely, 2^21521334044 is an apocalyptic number.

It is an amenable number.

21521334044 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.

21521334044 is a wasteful number, since it uses less digits than its factorization.

21521334044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 768619084 (or 768619082 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 29.

Adding to 21521334044 its reverse (44043312512), we get a palindrome (65564646556).

The spelling of 21521334044 in words is "twenty-one billion, five hundred twenty-one million, three hundred thirty-four thousand, forty-four".