21072785788 has 24 divisors (see below), whose sum is σ = 37033973424. Its totient is φ = 10491744000.

The previous prime is 21072785779. The next prime is 21072785807. The reversal of 21072785788 is 88758727012.

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, 930358 + ... + 952738.

It is an arithmetic number, because the mean of its divisors is an integer number (1543082226).

Almost surely, 2^21072785788 is an apocalyptic number.

It is an amenable number.

21072785788 is a deficient number, since it is larger than the sum of its proper divisors (15961187636).

21072785788 is a wasteful number, since it uses less digits than its factorization.

21072785788 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23373 (or 23371 counting only the distinct ones).

The product of its (nonzero) digits is 3512320, while the sum is 55.

The spelling of 21072785788 in words is "twenty-one billion, seventy-two million, seven hundred eighty-five thousand, seven hundred eighty-eight".