68709479891 has 4 divisors (see below), whose sum is σ = 73994824512. Its totient is φ = 63424135272.

The previous prime is 68709479879. The next prime is 68709479899. The reversal of 68709479891 is 19897490786.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19897490786 = 2 ⋅9948745393.

It is a cyclic number.

It is not a de Polignac number, because 68709479891 - 2³⁰ = 67635738067 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68709479899) 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, 2642672291 + ... + 2642672316.

It is an arithmetic number, because the mean of its divisors is an integer number (18498706128).

Almost surely, 2^68709479891 is an apocalyptic number.

68709479891 is a deficient number, since it is larger than the sum of its proper divisors (5285344621).

68709479891 is a wasteful number, since it uses less digits than its factorization.

68709479891 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5285344620.

The product of its (nonzero) digits is 54867456, while the sum is 68.

The spelling of 68709479891 in words is "sixty-eight billion, seven hundred nine million, four hundred seventy-nine thousand, eight hundred ninety-one".