681852851899691 has 2 divisors, whose sum is σ = 681852851899692. Its totient is φ = 681852851899690.

The previous prime is 681852851899603. The next prime is 681852851899727. The reversal of 681852851899691 is 196998158258186.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 681852851899691 - 2¹⁸ = 681852851637547 is a prime.

It is not a weakly prime, because it can be changed into another prime (681852851899091) 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, 340926425949845 + 340926425949846.

It is an arithmetic number, because the mean of its divisors is an integer number (340926425949846).

Almost surely, 2^{681852851899691} is an apocalyptic number.

681852851899691 is a deficient number, since it is larger than the sum of its proper divisors (1).

681852851899691 is an equidigital number, since it uses as much as digits as its factorization.

681852851899691 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5374771200, while the sum is 86.

The spelling of 681852851899691 in words is "six hundred eighty-one trillion, eight hundred fifty-two billion, eight hundred fifty-one million, eight hundred ninety-nine thousand, six hundred ninety-one".