68681591 has 4 divisors (see below), whose sum is σ = 74925384. Its totient is φ = 62437800.

The previous prime is 68681563. The next prime is 68681603. The reversal of 68681591 is 19518686.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 68681591 - 2⁶ = 68681527 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 (68681521) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3121880 + ... + 3121901.

It is an arithmetic number, because the mean of its divisors is an integer number (18731346).

Almost surely, 2^68681591 is an apocalyptic number.

68681591 is a deficient number, since it is larger than the sum of its proper divisors (6243793).

68681591 is a wasteful number, since it uses less digits than its factorization.

68681591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6243792.

The product of its digits is 103680, while the sum is 44.

The square root of 68681591 is about 8287.4357312742. The cubic root of 68681591 is about 409.5247139684.

The spelling of 68681591 in words is "sixty-eight million, six hundred eighty-one thousand, five hundred ninety-one".