681667766191 has 2 divisors, whose sum is σ = 681667766192. Its totient is φ = 681667766190.

The previous prime is 681667766183. The next prime is 681667766201. The reversal of 681667766191 is 191667766186.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 681667766191 - 2³ = 681667766183 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (681667763191) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 340833883095 + 340833883096.

It is an arithmetic number, because the mean of its divisors is an integer number (340833883096).

Almost surely, 2^681667766191 is an apocalyptic number.

681667766191 is a deficient number, since it is larger than the sum of its proper divisors (1).

681667766191 is an equidigital number, since it uses as much as digits as its factorization.

681667766191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27433728, while the sum is 64.

The spelling of 681667766191 in words is "six hundred eighty-one billion, six hundred sixty-seven million, seven hundred sixty-six thousand, one hundred ninety-one".