21122440444 has 12 divisors (see below), whose sum is σ = 42244880944. Its totient is φ = 9052474464.

The previous prime is 21122440441. The next prime is 21122440459. The reversal of 21122440444 is 44404422112.

It is a happy number.

21122440444 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 754372873 = 21122440444 / (2 + 1 + 1 + 2 + 2 + 4 + 4 + 0 + 4 + 4 + 4).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21122440441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 377186409 + ... + 377186464.

Almost surely, 2^21122440444 is an apocalyptic number.

It is an amenable number.

21122440444 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.

21122440444 is a wasteful number, since it uses less digits than its factorization.

21122440444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 754372884 (or 754372882 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 28.

Adding to 21122440444 its reverse (44404422112), we get a palindrome (65526862556).

The spelling of 21122440444 in words is "twenty-one billion, one hundred twenty-two million, four hundred forty thousand, four hundred forty-four".