19989905808 has 40 divisors (see below), whose sum is σ = 52012122400. Its totient is φ = 6615362304.

The previous prime is 19989905723. The next prime is 19989905867. The reversal of 19989905808 is 80850998991.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1491373 + ... + 1504716.

It is an arithmetic number, because the mean of its divisors is an integer number (1300303060).

Almost surely, 2^19989905808 is an apocalyptic number.

It is an amenable number.

19989905808 is an abundant number, since it is smaller than the sum of its proper divisors (32022216592).

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

19989905808 is a wasteful number, since it uses less digits than its factorization.

19989905808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2996239 (or 2996233 counting only the distinct ones).

The product of its (nonzero) digits is 16796160, while the sum is 66.

The spelling of 19989905808 in words is "nineteen billion, nine hundred eighty-nine million, nine hundred five thousand, eight hundred eight".