21680584728 has 32 divisors (see below), whose sum is σ = 59128868160. Its totient is φ = 6569874080.

The previous prime is 21680584663. The next prime is 21680584729. The reversal of 21680584728 is 82748508612.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21680584729) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41061450 + ... + 41061977.

It is an arithmetic number, because the mean of its divisors is an integer number (1847777130).

Almost surely, 2^21680584728 is an apocalyptic number.

It is an amenable number.

21680584728 is an abundant number, since it is smaller than the sum of its proper divisors (37448283432).

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

21680584728 is a wasteful number, since it uses less digits than its factorization.

21680584728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82123447 (or 82123443 counting only the distinct ones).

The product of its (nonzero) digits is 1720320, while the sum is 51.

The spelling of 21680584728 in words is "twenty-one billion, six hundred eighty million, five hundred eighty-four thousand, seven hundred twenty-eight".