21043321424 has 20 divisors (see below), whose sum is σ = 41719609536. Its totient is φ = 10276970592.

The previous prime is 21043321399. The next prime is 21043321457. The reversal of 21043321424 is 42412334012.

It is a junction number, because it is equal to n+sod(n) for n = 21043321393 and 21043321402.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15292424 + ... + 15293799.

Almost surely, 2^21043321424 is an apocalyptic number.

It is an amenable number.

21043321424 is a deficient number, since it is larger than the sum of its proper divisors (20676288112).

21043321424 is a wasteful number, since it uses less digits than its factorization.

21043321424 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30586274 (or 30586268 counting only the distinct ones).

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

Adding to 21043321424 its reverse (42412334012), we get a palindrome (63455655436).

The spelling of 21043321424 in words is "twenty-one billion, forty-three million, three hundred twenty-one thousand, four hundred twenty-four".