195781639679 has 4 divisors (see below), whose sum is σ = 201073035384. Its totient is φ = 190490243976.

The previous prime is 195781639657. The next prime is 195781639681. The reversal of 195781639679 is 976936187591.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-195781639679 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (195781639619) 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, 2645697797 + ... + 2645697870.

It is an arithmetic number, because the mean of its divisors is an integer number (50268258846).

Almost surely, 2^195781639679 is an apocalyptic number.

195781639679 is a deficient number, since it is larger than the sum of its proper divisors (5291395705).

195781639679 is an equidigital number, since it uses as much as digits as its factorization.

195781639679 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5291395704.

The product of its digits is 154314720, while the sum is 71.

The spelling of 195781639679 in words is "one hundred ninety-five billion, seven hundred eighty-one million, six hundred thirty-nine thousand, six hundred seventy-nine".