21043221344 has 24 divisors (see below), whose sum is σ = 42548542848. Its totient is φ = 10237242240.

The previous prime is 21043221343. The next prime is 21043221359. The reversal of 21043221344 is 44312234012.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043221343) 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, 8885312 + ... + 8887679.

It is an arithmetic number, because the mean of its divisors is an integer number (1772855952).

Almost surely, 2^21043221344 is an apocalyptic number.

It is an amenable number.

21043221344 is an abundant number, since it is smaller than the sum of its proper divisors (21505321504).

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

21043221344 is a wasteful number, since it uses less digits than its factorization.

21043221344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17773038 (or 17773030 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 26.

Adding to 21043221344 its reverse (44312234012), we get a palindrome (65355455356).

The spelling of 21043221344 in words is "twenty-one billion, forty-three million, two hundred twenty-one thousand, three hundred forty-four".