68905861891 has 2 divisors, whose sum is σ = 68905861892. Its totient is φ = 68905861890.

The previous prime is 68905861823. The next prime is 68905861931. The reversal of 68905861891 is 19816850986.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 68905861891 - 2⁷ = 68905861763 is a prime.

It is not a weakly prime, because it can be changed into another prime (68905861691) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 34452930945 + 34452930946.

It is an arithmetic number, because the mean of its divisors is an integer number (34452930946).

Almost surely, 2^68905861891 is an apocalyptic number.

68905861891 is a deficient number, since it is larger than the sum of its proper divisors (1).

68905861891 is an equidigital number, since it uses as much as digits as its factorization.

68905861891 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 7464960, while the sum is 61.

The spelling of 68905861891 in words is "sixty-eight billion, nine hundred five million, eight hundred sixty-one thousand, eight hundred ninety-one".