68209391 has 4 divisors (see below), whose sum is σ = 68392632. Its totient is φ = 68026152.

The previous prime is 68209343. The next prime is 68209433. The reversal of 68209391 is 19390286.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19390286 = 2 ⋅9695143.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68209391 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 (68209091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 91061 + ... + 91806.

It is an arithmetic number, because the mean of its divisors is an integer number (17098158).

Almost surely, 2^68209391 is an apocalyptic number.

68209391 is a deficient number, since it is larger than the sum of its proper divisors (183241).

68209391 is a wasteful number, since it uses less digits than its factorization.

68209391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 183240.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 68209391 is about 8258.8976867376. The cubic root of 68209391 is about 408.5840327866.

The spelling of 68209391 in words is "sixty-eight million, two hundred nine thousand, three hundred ninety-one".