19728733491 has 10 divisors (see below), whose sum is σ = 29471318052. Its totient is φ = 13152488940.

The previous prime is 19728733477. The next prime is 19728733501. The reversal of 19728733491 is 19433782791.

19728733491 is a `hidden beast` number, since 1 + 9 + 72 + 87 + 3 + 3 + 491 = 666.

It is not a de Polignac number, because 19728733491 - 2⁷ = 19728733363 is a prime.

It is not an unprimeable number, because it can be changed into a prime (19728733421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 121782225 + ... + 121782386.

Almost surely, 2^19728733491 is an apocalyptic number.

19728733491 is a deficient number, since it is larger than the sum of its proper divisors (9742584561).

19728733491 is an equidigital number, since it uses as much as digits as its factorization.

19728733491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 243564623 (or 243564614 counting only the distinct ones).

The product of its digits is 2286144, while the sum is 54.

The spelling of 19728733491 in words is "nineteen billion, seven hundred twenty-eight million, seven hundred thirty-three thousand, four hundred ninety-one".