19803684128 has 18 divisors (see below), whose sum is σ = 38990070441. Its totient is φ = 9901444032.

The previous prime is 19803684079. The next prime is 19803684133. The reversal of 19803684128 is 82148630891.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in 2 ways, for example, as 10788561424 + 9015122704 = 103868^2 + 94948^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=99508.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 783626 + ... + 808502.

Almost surely, 2^19803684128 is an apocalyptic number.

It is an amenable number.

19803684128 is a deficient number, since it is larger than the sum of its proper divisors (19186386313).

19803684128 is an frugal number, since it uses more digits than its factorization.

19803684128 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49764 (or 24879 counting only the distinct ones).

The product of its (nonzero) digits is 663552, while the sum is 50.

Multiplying 19803684128 by its sum of digits (50), we get a square (990184206400 = 995080²).

The spelling of 19803684128 in words is "nineteen billion, eight hundred three million, six hundred eighty-four thousand, one hundred twenty-eight".