21205328404 has 36 divisors (see below), whose sum is σ = 42298415040. Its totient is φ = 9271959840.

The previous prime is 21205328393. The next prime is 21205328407. The reversal of 21205328404 is 40482350212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21205328407) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 812652 + ... + 838339.

Almost surely, 2^21205328404 is an apocalyptic number.

It is an amenable number.

21205328404 is a deficient number, since it is larger than the sum of its proper divisors (21093086636).

21205328404 is a wasteful number, since it uses less digits than its factorization.

21205328404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1651040 (or 1651025 counting only the distinct ones).

The product of its (nonzero) digits is 15360, while the sum is 31.

Adding to 21205328404 its reverse (40482350212), we get a palindrome (61687678616).

The spelling of 21205328404 in words is "twenty-one billion, two hundred five million, three hundred twenty-eight thousand, four hundred four".