168391 has 2 divisors, whose sum is σ = 168392. Its totient is φ = 168390.

The previous prime is 168353. The next prime is 168409. The reversal of 168391 is 193861.

It is a happy number.

168391 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is an emirp because it is prime and its reverse (193861) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 168391 - 2⁷ = 168263 is a prime.

It is a Chen prime.

It is an Ulam number.

168391 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (168331) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84195 + 84196.

It is an arithmetic number, because the mean of its divisors is an integer number (84196).

2¹⁶⁸³⁹¹ is an apocalyptic number.

168391 is a deficient number, since it is larger than the sum of its proper divisors (1).

168391 is an equidigital number, since it uses as much as digits as its factorization.

168391 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1296, while the sum is 28.

The square root of 168391 is about 410.3547245981. The cubic root of 168391 is about 55.2212574782.

The spelling of 168391 in words is "one hundred sixty-eight thousand, three hundred ninety-one".