168539391 has 6 divisors (see below), whose sum is σ = 243445800. Its totient is φ = 112359588.

The previous prime is 168539369. The next prime is 168539447. The reversal of 168539391 is 193935861.

It is not a de Polignac number, because 168539391 - 2⁵ = 168539359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168519391) 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 5 ways as a sum of consecutive naturals, for example, 9363291 + ... + 9363308.

It is an arithmetic number, because the mean of its divisors is an integer number (40574300).

Almost surely, 2^168539391 is an apocalyptic number.

168539391 is a deficient number, since it is larger than the sum of its proper divisors (74906409).

168539391 is a wasteful number, since it uses less digits than its factorization.

168539391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18726605 (or 18726602 counting only the distinct ones).

The product of its digits is 174960, while the sum is 45.

The square root of 168539391 is about 12982.2721817099. The cubic root of 168539391 is about 552.3747357004.

It can be divided in two parts, 16853 and 9391, that added together give a square (26244 = 162²).

The spelling of 168539391 in words is "one hundred sixty-eight million, five hundred thirty-nine thousand, three hundred ninety-one".