195891639217 has 8 divisors (see below), whose sum is σ = 208304872776. Its totient is φ = 183577316352.

The previous prime is 195891639197. The next prime is 195891639221. The reversal of 195891639217 is 712936198591.

195891639217 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 4 ways, for example, as 21828289536 + 174063349681 = 147744^2 + 417209^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-195891639217 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (195891639257) 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 7 ways as a sum of consecutive naturals, for example, 24723588 + ... + 24731509.

It is an arithmetic number, because the mean of its divisors is an integer number (26038109097).

Almost surely, 2^195891639217 is an apocalyptic number.

195891639217 is a gapful number since it is divisible by the number (17) formed by its first and last digit.

It is an amenable number.

195891639217 is a deficient number, since it is larger than the sum of its proper divisors (12413233559).

195891639217 is a wasteful number, since it uses less digits than its factorization.

195891639217 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 49455347.

The product of its digits is 7348320, while the sum is 61.

The spelling of 195891639217 in words is "one hundred ninety-five billion, eight hundred ninety-one million, six hundred thirty-nine thousand, two hundred seventeen".