168928398081 has 27 divisors (see below), whose sum is σ = 259237564131. Its totient is φ = 105981136704.

The previous prime is 168928398049. The next prime is 168928398083. The reversal of 168928398081 is 180893829861.

It is a happy number.

The square root of 168928398081 is 411009.

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

168928398081 is a `hidden beast` number, since 168 + 9 + 2 + 8 + 398 + 0 + 81 = 666.

It can be written as a sum of positive squares in only one way, i.e., 131518649025 + 37409749056 = 362655^2 + 193416^2 .

It is not a de Polignac number, because 168928398081 - 2⁵ = 168928398049 is a prime.

It is a super-2 number, since 2×168928398081² (a number of 23 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (168928398083) by changing a digit.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 20957430 + ... + 20965488.

Almost surely, 2^168928398081 is an apocalyptic number.

168928398081 is the 411009-th square number.

168928398081 is the 205505-th centered octagonal number.

It is an amenable number.

168928398081 is a deficient number, since it is larger than the sum of its proper divisors (90309166050).

168928398081 is an frugal number, since it uses more digits than its factorization.

168928398081 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16158 (or 8079 counting only the distinct ones).

The product of its (nonzero) digits is 11943936, while the sum is 63.

It can be divided in two parts, 168928 and 398081, that added together give a square (567009 = 753²).

The spelling of 168928398081 in words is "one hundred sixty-eight billion, nine hundred twenty-eight million, three hundred ninety-eight thousand, eighty-one".