68816591 has 4 divisors (see below), whose sum is σ = 68955000. Its totient is φ = 68678184.

The previous prime is 68816569. The next prime is 68816609. The reversal of 68816591 is 19561886.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-68816591 is a prime.

It is a super-2 number, since 2×68816591² = 9471446393722562, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (68816521) 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, 68456 + ... + 69453.

It is an arithmetic number, because the mean of its divisors is an integer number (17238750).

Almost surely, 2^68816591 is an apocalyptic number.

68816591 is a deficient number, since it is larger than the sum of its proper divisors (138409).

68816591 is a wasteful number, since it uses less digits than its factorization.

68816591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 138408.

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

The square root of 68816591 is about 8295.5765923774. The cubic root of 68816591 is about 409.7928578866.

The spelling of 68816591 in words is "sixty-eight million, eight hundred sixteen thousand, five hundred ninety-one".