168656813 has 16 divisors (see below), whose sum is σ = 193097520. Its totient is φ = 145929216.

The previous prime is 168656809. The next prime is 168656819. The reversal of 168656813 is 318656861.

It can be written as a sum of positive squares in 8 ways, for example, as 55383364 + 113273449 = 7442^2 + 10643^2 .

It is a cyclic number.

It is not a de Polignac number, because 168656813 - 2² = 168656809 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168656819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 58031 + ... + 60867.

It is an arithmetic number, because the mean of its divisors is an integer number (12068595).

Almost surely, 2^168656813 is an apocalyptic number.

168656813 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

168656813 is a deficient number, since it is larger than the sum of its proper divisors (24440707).

168656813 is a wasteful number, since it uses less digits than its factorization.

168656813 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3136.

The product of its digits is 207360, while the sum is 44.

The square root of 168656813 is about 12986.7937921567. The cubic root of 168656813 is about 552.5029864092.

The spelling of 168656813 in words is "one hundred sixty-eight million, six hundred fifty-six thousand, eight hundred thirteen".