19998538792 has 8 divisors (see below), whose sum is σ = 37497260250. Its totient is φ = 9999269392.

The previous prime is 19998538759. The next prime is 19998538853. The reversal of 19998538792 is 29783589991.

It can be written as a sum of positive squares in only one way, i.e., 19475318916 + 523219876 = 139554^2 + 22874^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1249908667 + ... + 1249908682.

Almost surely, 2^19998538792 is an apocalyptic number.

It is an amenable number.

19998538792 is a deficient number, since it is larger than the sum of its proper divisors (17498721458).

19998538792 is a wasteful number, since it uses less digits than its factorization.

19998538792 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2499817355 (or 2499817351 counting only the distinct ones).

The product of its digits is 88179840, while the sum is 70.

The spelling of 19998538792 in words is "nineteen billion, nine hundred ninety-eight million, five hundred thirty-eight thousand, seven hundred ninety-two".