168516316781 has 4 divisors (see below), whose sum is σ = 171372525600. Its totient is φ = 165660107964.

The previous prime is 168516316741. The next prime is 168516316799. The reversal of 168516316781 is 187613615861.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 168516316781 - 2¹⁰ = 168516315757 is a prime.

It is a super-2 number, since 2×168516316781² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168516316741) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1428104321 + ... + 1428104438.

It is an arithmetic number, because the mean of its divisors is an integer number (42843131400).

Almost surely, 2^168516316781 is an apocalyptic number.

It is an amenable number.

168516316781 is a deficient number, since it is larger than the sum of its proper divisors (2856208819).

168516316781 is an equidigital number, since it uses as much as digits as its factorization.

168516316781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2856208818.

The product of its digits is 1451520, while the sum is 53.

The spelling of 168516316781 in words is "one hundred sixty-eight billion, five hundred sixteen million, three hundred sixteen thousand, seven hundred eighty-one".