168723021805 has 16 divisors (see below), whose sum is σ = 218743185024. Its totient is φ = 124194818880.

The previous prime is 168723021767. The next prime is 168723021809. The reversal of 168723021805 is 508120327861.

It is a de Polignac number, because none of the positive numbers 2^k-168723021805 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168723021809) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4152999 + ... + 4193428.

It is an arithmetic number, because the mean of its divisors is an integer number (13671449064).

Almost surely, 2^168723021805 is an apocalyptic number.

It is an amenable number.

168723021805 is a deficient number, since it is larger than the sum of its proper divisors (50020163219).

168723021805 is a wasteful number, since it uses less digits than its factorization.

168723021805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8346756.

The product of its (nonzero) digits is 161280, while the sum is 43.

The spelling of 168723021805 in words is "one hundred sixty-eight billion, seven hundred twenty-three million, twenty-one thousand, eight hundred five".