21204405552 has 40 divisors (see below), whose sum is σ = 59757871680. Its totient is φ = 6425577280.

The previous prime is 21204405527. The next prime is 21204405581. The reversal of 21204405552 is 25550440212.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 20079402 + ... + 20080457.

It is an arithmetic number, because the mean of its divisors is an integer number (1493946792).

Almost surely, 2^21204405552 is an apocalyptic number.

21204405552 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21204405552 is an abundant number, since it is smaller than the sum of its proper divisors (38553466128).

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

21204405552 is a wasteful number, since it uses less digits than its factorization.

21204405552 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40159881 (or 40159875 counting only the distinct ones).

The product of its (nonzero) digits is 16000, while the sum is 30.

Adding to 21204405552 its reverse (25550440212), we get a palindrome (46754845764).

The spelling of 21204405552 in words is "twenty-one billion, two hundred four million, four hundred five thousand, five hundred fifty-two".