19887915866 has 64 divisors (see below), whose sum is σ = 39437664000. Its totient is φ = 7453591488.

The previous prime is 19887915857. The next prime is 19887915869. The reversal of 19887915866 is 66851978891.

It is a junction number, because it is equal to n+sod(n) for n = 19887915796 and 19887915805.

It is not an unprimeable number, because it can be changed into a prime (19887915869) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110756 + ... + 228128.

It is an arithmetic number, because the mean of its divisors is an integer number (616213500).

Almost surely, 2^19887915866 is an apocalyptic number.

19887915866 is a deficient number, since it is larger than the sum of its proper divisors (19549748134).

19887915866 is a wasteful number, since it uses less digits than its factorization.

19887915866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 117428 (or 117414 counting only the distinct ones).

The product of its digits is 52254720, while the sum is 68.

The spelling of 19887915866 in words is "nineteen billion, eight hundred eighty-seven million, nine hundred fifteen thousand, eight hundred sixty-six".