68320816081 has 12 divisors (see below), whose sum is σ = 79878673908. Its totient is φ = 58263428832.

The previous prime is 68320816079. The next prime is 68320816097. The reversal of 68320816081 is 18061802386.

It can be written as a sum of positive squares in 2 ways, for example, as 67589600400 + 731215681 = 259980^2 + 27041^2 .

It is not a de Polignac number, because 68320816081 - 2¹ = 68320816079 is a prime.

It is a super-2 number, since 2×68320816081² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (68320816181) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3529186 + ... + 3548491.

It is an arithmetic number, because the mean of its divisors is an integer number (6656556159).

Almost surely, 2^68320816081 is an apocalyptic number.

It is an amenable number.

68320816081 is a deficient number, since it is larger than the sum of its proper divisors (11557857827).

68320816081 is a wasteful number, since it uses less digits than its factorization.

68320816081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7077888 (or 7077881 counting only the distinct ones).

The product of its (nonzero) digits is 110592, while the sum is 43.

The spelling of 68320816081 in words is "sixty-eight billion, three hundred twenty million, eight hundred sixteen thousand, eighty-one".