68355978181 has 4 divisors (see below), whose sum is σ = 72376918092. Its totient is φ = 64335038272.

The previous prime is 68355978169. The next prime is 68355978209. The reversal of 68355978181 is 18187955386.

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

It can be written as a sum of positive squares in 2 ways, for example, as 62005482081 + 6350496100 = 249009^2 + 79690^2 .

It is not a de Polignac number, because 68355978181 - 2¹¹ = 68355976133 is a prime.

It is a super-2 number, since 2×68355978181² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68355978281) 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, 2010469930 + ... + 2010469963.

It is an arithmetic number, because the mean of its divisors is an integer number (18094229523).

Almost surely, 2^68355978181 is an apocalyptic number.

It is an amenable number.

68355978181 is a deficient number, since it is larger than the sum of its proper divisors (4020939911).

68355978181 is a wasteful number, since it uses less digits than its factorization.

68355978181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4020939910.

The product of its digits is 14515200, while the sum is 61.

The spelling of 68355978181 in words is "sixty-eight billion, three hundred fifty-five million, nine hundred seventy-eight thousand, one hundred eighty-one".