21785319788 has 12 divisors (see below), whose sum is σ = 38207735832. Its totient is φ = 10868823840.

The previous prime is 21785319737. The next prime is 21785319793. The reversal of 21785319788 is 88791358712.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5956958 + ... + 5960613.

It is an arithmetic number, because the mean of its divisors is an integer number (3183977986).

Almost surely, 2^21785319788 is an apocalyptic number.

It is an amenable number.

21785319788 is a deficient number, since it is larger than the sum of its proper divisors (16422416044).

21785319788 is a wasteful number, since it uses less digits than its factorization.

21785319788 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11918032 (or 11918030 counting only the distinct ones).

The product of its digits is 6773760, while the sum is 59.

The spelling of 21785319788 in words is "twenty-one billion, seven hundred eighty-five million, three hundred nineteen thousand, seven hundred eighty-eight".