685397191 has 2 divisors, whose sum is σ = 685397192. Its totient is φ = 685397190.

The previous prime is 685397179. The next prime is 685397231. The reversal of 685397191 is 191793586.

685397191 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 685397191 - 2¹¹ = 685395143 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (685397291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342698595 + 342698596.

It is an arithmetic number, because the mean of its divisors is an integer number (342698596).

Almost surely, 2^685397191 is an apocalyptic number.

685397191 is a deficient number, since it is larger than the sum of its proper divisors (1).

685397191 is an equidigital number, since it uses as much as digits as its factorization.

685397191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 408240, while the sum is 49.

The square root of 685397191 is about 26180.0915009860. The cubic root of 685397191 is about 881.6863286952.

The spelling of 685397191 in words is "six hundred eighty-five million, three hundred ninety-seven thousand, one hundred ninety-one".