685397189 has 4 divisors (see below), whose sum is σ = 686192256. Its totient is φ = 684602124.

The previous prime is 685397179. The next prime is 685397191. The reversal of 685397189 is 981793586.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 981793586 = 2 ⋅490896793.

It is a cyclic number.

It is not a de Polignac number, because 685397189 - 2⁴ = 685397173 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685397149) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 396239 + ... + 397964.

It is an arithmetic number, because the mean of its divisors is an integer number (171548064).

Almost surely, 2^685397189 is an apocalyptic number.

It is an amenable number.

685397189 is a deficient number, since it is larger than the sum of its proper divisors (795067).

685397189 is an equidigital number, since it uses as much as digits as its factorization.

685397189 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 795066.

The product of its digits is 3265920, while the sum is 56.

The square root of 685397189 is about 26180.0914627890. The cubic root of 685397189 is about 881.6863278376.

It can be divided in two parts, 685397 and 189, that added together give a palindrome (685586).

The spelling of 685397189 in words is "six hundred eighty-five million, three hundred ninety-seven thousand, one hundred eighty-nine".