191638779393 has 32 divisors (see below), whose sum is σ = 270514483200. Its totient is φ = 120340512000.

The previous prime is 191638779391. The next prime is 191638779461. The reversal of 191638779393 is 393977836191.

191638779393 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 191638779393 - 2¹ = 191638779391 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (191638779391) 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 31 ways as a sum of consecutive naturals, for example, 7095048 + ... + 7122006.

It is an arithmetic number, because the mean of its divisors is an integer number (8453577600).

Almost surely, 2^191638779393 is an apocalyptic number.

It is an amenable number.

191638779393 is a deficient number, since it is larger than the sum of its proper divisors (78875703807).

191638779393 is a wasteful number, since it uses less digits than its factorization.

191638779393 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27693.

The product of its digits is 46294416, while the sum is 66.

The spelling of 191638779393 in words is "one hundred ninety-one billion, six hundred thirty-eight million, seven hundred seventy-nine thousand, three hundred ninety-three".