68391305958521 has 12 divisors (see below), whose sum is σ = 85677020652132. Its totient is φ = 54111802516128.

The previous prime is 68391305958491. The next prime is 68391305958527. The reversal of 68391305958521 is 12585950319386.

It can be written as a sum of positive squares in 2 ways, for example, as 47054990192896 + 21336315765625 = 6859664^2 + 4619125^2 .

It is not a de Polignac number, because 68391305958521 - 2²⁶ = 68391238849657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (68391305958527) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 53682343130 + ... + 53682344403.

It is an arithmetic number, because the mean of its divisors is an integer number (7139751721011).

Almost surely, 2^{68391305958521} is an apocalyptic number.

It is an amenable number.

68391305958521 is a deficient number, since it is larger than the sum of its proper divisors (17285714693611).

68391305958521 is a wasteful number, since it uses less digits than its factorization.

68391305958521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 107364687560 (or 107364687553 counting only the distinct ones).

The product of its (nonzero) digits is 69984000, while the sum is 65.

The spelling of 68391305958521 in words is "sixty-eight trillion, three hundred ninety-one billion, three hundred five million, nine hundred fifty-eight thousand, five hundred twenty-one".