68391791 has 16 divisors (see below), whose sum is σ = 75295584. Its totient is φ = 61737984.

The previous prime is 68391779. The next prime is 68391793. The reversal of 68391791 is 19719386.

It is a cyclic number.

It is not a de Polignac number, because 68391791 - 2¹⁸ = 68129647 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68391793) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 202775 + ... + 203111.

It is an arithmetic number, because the mean of its divisors is an integer number (4705974).

Almost surely, 2^68391791 is an apocalyptic number.

68391791 is a deficient number, since it is larger than the sum of its proper divisors (6903793).

68391791 is a wasteful number, since it uses less digits than its factorization.

68391791 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 650.

The product of its digits is 81648, while the sum is 44.

The square root of 68391791 is about 8269.9329501514. The cubic root of 68391791 is about 408.9479093477.

The spelling of 68391791 in words is "sixty-eight million, three hundred ninety-one thousand, seven hundred ninety-one".