191666388065 has 16 divisors (see below), whose sum is σ = 244600849920. Its totient is φ = 143765383680.

The previous prime is 191666388029. The next prime is 191666388071. The reversal of 191666388065 is 560883666191.

It is not a de Polignac number, because 191666388065 - 2¹⁸ = 191666125921 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 191666387995 and 191666388013.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10390481 + ... + 10408910.

It is an arithmetic number, because the mean of its divisors is an integer number (15287553120).

Almost surely, 2^191666388065 is an apocalyptic number.

It is an amenable number.

191666388065 is a deficient number, since it is larger than the sum of its proper divisors (52934461855).

191666388065 is a wasteful number, since it uses less digits than its factorization.

191666388065 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20799512.

The product of its (nonzero) digits is 11197440, while the sum is 59.

The spelling of 191666388065 in words is "one hundred ninety-one billion, six hundred sixty-six million, three hundred eighty-eight thousand, sixty-five".