21043443004 has 12 divisors (see below), whose sum is σ = 36827935200. Its totient is φ = 10521175808.

The previous prime is 21043442977. The next prime is 21043443007. The reversal of 21043443004 is 40034434012.

It is a self number, because there is not a number n which added to its sum of digits gives 21043443004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21043443007) 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, 42469 + ... + 209500.

It is an arithmetic number, because the mean of its divisors is an integer number (3068994600).

Almost surely, 2^21043443004 is an apocalyptic number.

It is an amenable number.

21043443004 is a deficient number, since it is larger than the sum of its proper divisors (15784492196).

21043443004 is a wasteful number, since it uses less digits than its factorization.

21043443004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 272852 (or 272850 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 25.

Adding to 21043443004 its reverse (40034434012), we get a palindrome (61077877016).

The spelling of 21043443004 in words is "twenty-one billion, forty-three million, four hundred forty-three thousand, four".