21798785550 has 48 divisors (see below), whose sum is σ = 54384769152. Its totient is φ = 5778194400.

The previous prime is 21798785549. The next prime is 21798785563. The reversal of 21798785550 is 5558789712.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 410056 + ... + 460155.

It is an arithmetic number, because the mean of its divisors is an integer number (1133016024).

Almost surely, 2^21798785550 is an apocalyptic number.

21798785550 is an abundant number, since it is smaller than the sum of its proper divisors (32585983602).

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

21798785550 is a wasteful number, since it uses less digits than its factorization.

21798785550 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 870393 (or 870388 counting only the distinct ones).

The product of its (nonzero) digits is 7056000, while the sum is 57.

The spelling of 21798785550 in words is "twenty-one billion, seven hundred ninety-eight million, seven hundred eighty-five thousand, five hundred fifty".