21205530744 has 32 divisors (see below), whose sum is σ = 53280240000. Its totient is φ = 7032988512.

The previous prime is 21205530739. The next prime is 21205530757. The reversal of 21205530744 is 44703550212.

It is a congruent number.

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, 2215234 + ... + 2224785.

It is an arithmetic number, because the mean of its divisors is an integer number (1665007500).

Almost surely, 2^21205530744 is an apocalyptic number.

21205530744 is a gapful number since it is divisible by the number (24) formed by its first and last digit.

It is an amenable number.

21205530744 is an abundant number, since it is smaller than the sum of its proper divisors (32074709256).

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

21205530744 is a wasteful number, since it uses less digits than its factorization.

21205530744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4440227 (or 4440223 counting only the distinct ones).

The product of its (nonzero) digits is 33600, while the sum is 33.

The spelling of 21205530744 in words is "twenty-one billion, two hundred five million, five hundred thirty thousand, seven hundred forty-four".