19663891984 has 45 divisors (see below), whose sum is σ = 41890327311. Its totient is φ = 8935328160.

The previous prime is 19663891969. The next prime is 19663892029. The reversal of 19663891984 is 48919836691.

The square root of 19663891984 is 140228.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 6168439 + ... + 6171625.

Almost surely, 2^19663891984 is an apocalyptic number.

19663891984 is the 140228-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19663891984

19663891984 is an abundant number, since it is smaller than the sum of its proper divisors (22226435327).

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

19663891984 is an frugal number, since it uses more digits than its factorization.

19663891984 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6404 (or 3200 counting only the distinct ones).

The product of its digits is 20155392, while the sum is 64.

Multiplying 19663891984 by its sum of digits (64), we get a square (1258489086976 = 1121824²).

The spelling of 19663891984 in words is "nineteen billion, six hundred sixty-three million, eight hundred ninety-one thousand, nine hundred eighty-four".