21265213044 has 24 divisors (see below), whose sum is σ = 49621188960. Its totient is φ = 7088067424.

The previous prime is 21265213031. The next prime is 21265213051. The reversal of 21265213044 is 44031256212.

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 7 ways as a sum of consecutive naturals, for example, 468247 + ... + 511649.

It is an arithmetic number, because the mean of its divisors is an integer number (2067549540).

Almost surely, 2^21265213044 is an apocalyptic number.

It is an amenable number.

21265213044 is an abundant number, since it is smaller than the sum of its proper divisors (28355975916).

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

21265213044 is a wasteful number, since it uses less digits than its factorization.

21265213044 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84239 (or 84237 counting only the distinct ones).

The product of its (nonzero) digits is 11520, while the sum is 30.

Adding to 21265213044 its reverse (44031256212), we get a palindrome (65296469256).

The spelling of 21265213044 in words is "twenty-one billion, two hundred sixty-five million, two hundred thirteen thousand, forty-four".