21022768788 has 24 divisors (see below), whose sum is σ = 56060716992. Its totient is φ = 6006505344.

The previous prime is 21022768771. The next prime is 21022768853. The reversal of 21022768788 is 88786722012.

It is a self number, because there is not a number n which added to its sum of digits gives 21022768788.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 125135445 + ... + 125135612.

It is an arithmetic number, because the mean of its divisors is an integer number (2335863208).

Almost surely, 2^21022768788 is an apocalyptic number.

21022768788 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

21022768788 is an abundant number, since it is smaller than the sum of its proper divisors (35037948204).

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

21022768788 is a wasteful number, since it uses less digits than its factorization.

21022768788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 250271071 (or 250271069 counting only the distinct ones).

The product of its (nonzero) digits is 1204224, while the sum is 51.

The spelling of 21022768788 in words is "twenty-one billion, twenty-two million, seven hundred sixty-eight thousand, seven hundred eighty-eight".