19728823791 has 4 divisors (see below), whose sum is σ = 26305098392. Its totient is φ = 13152549192.

The previous prime is 19728823783. The next prime is 19728823841. The reversal of 19728823791 is 19732882791.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 19728823791 - 2³ = 19728823783 is a prime.

It is a super-2 number, since 2×19728823791² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19728823711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3288137296 + ... + 3288137301.

It is an arithmetic number, because the mean of its divisors is an integer number (6576274598).

Almost surely, 2^19728823791 is an apocalyptic number.

19728823791 is a deficient number, since it is larger than the sum of its proper divisors (6576274601).

19728823791 is an equidigital number, since it uses as much as digits as its factorization.

19728823791 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6576274600.

The product of its digits is 3048192, while the sum is 57.

The spelling of 19728823791 in words is "nineteen billion, seven hundred twenty-eight million, eight hundred twenty-three thousand, seven hundred ninety-one".