21440355312 has 20 divisors (see below), whose sum is σ = 55387584680. Its totient is φ = 7146785088.

The previous prime is 21440355289. The next prime is 21440355319. The reversal of 21440355312 is 21355304412.

It is a self number, because there is not a number n which added to its sum of digits gives 21440355312.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21440355319) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 223336987 + ... + 223337082.

It is an arithmetic number, because the mean of its divisors is an integer number (2769379234).

Almost surely, 2^21440355312 is an apocalyptic number.

It is an amenable number.

21440355312 is an abundant number, since it is smaller than the sum of its proper divisors (33947229368).

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

21440355312 is a wasteful number, since it uses less digits than its factorization.

21440355312 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 446674080 (or 446674074 counting only the distinct ones).

The product of its (nonzero) digits is 14400, while the sum is 30.

Adding to 21440355312 its reverse (21355304412), we get a palindrome (42795659724).

The spelling of 21440355312 in words is "twenty-one billion, four hundred forty million, three hundred fifty-five thousand, three hundred twelve".