168811691689 has 9 divisors (see below), whose sum is σ = 170509297143. Its totient is φ = 167130834792.

The previous prime is 168811691681. The next prime is 168811691707. The reversal of 168811691689 is 986196118861.

The square root of 168811691689 is 410867.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 79590001689 + 89221690000 = 282117^2 + 298700^2 .

It is not a de Polignac number, because 168811691689 - 2³ = 168811691681 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 168811691689.

It is not an unprimeable number, because it can be changed into a prime (168811691681) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 42317307 + ... + 42321295.

Almost surely, 2^168811691689 is an apocalyptic number.

168811691689 is the 410867-th square number.

168811691689 is the 205434-th centered octagonal number.

It is an amenable number.

168811691689 is a deficient number, since it is larger than the sum of its proper divisors (1697605454).

168811691689 is an frugal number, since it uses more digits than its factorization.

168811691689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8184 (or 4092 counting only the distinct ones).

The product of its digits is 8957952, while the sum is 64.

Multiplying 168811691689 by its sum of digits (64), we get a square (10803948268096 = 3286936²).

The spelling of 168811691689 in words is "one hundred sixty-eight billion, eight hundred eleven million, six hundred ninety-one thousand, six hundred eighty-nine".