685549169 has 2 divisors, whose sum is σ = 685549170. Its totient is φ = 685549168.

The previous prime is 685549147. The next prime is 685549181. The reversal of 685549169 is 961945586.

It is a happy number.

685549169 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 680531569 + 5017600 = 26087^2 + 2240^2 .

It is a cyclic number.

It is not a de Polignac number, because 685549169 - 2²⁴ = 668771953 is a prime.

It is a super-2 number, since 2×685549169² = 939955326233181122, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 685549169.

It is not a weakly prime, because it can be changed into another prime (685549369) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342774584 + 342774585.

It is an arithmetic number, because the mean of its divisors is an integer number (342774585).

Almost surely, 2^685549169 is an apocalyptic number.

It is an amenable number.

685549169 is a deficient number, since it is larger than the sum of its proper divisors (1).

685549169 is an equidigital number, since it uses as much as digits as its factorization.

685549169 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2332800, while the sum is 53.

The square root of 685549169 is about 26182.9938891640. The cubic root of 685549169 is about 881.7514914086.

The spelling of 685549169 in words is "six hundred eighty-five million, five hundred forty-nine thousand, one hundred sixty-nine".