685078169 has 2 divisors, whose sum is σ = 685078170. Its totient is φ = 685078168.

The previous prime is 685078153. The next prime is 685078181. The reversal of 685078169 is 961870586.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 676000000 + 9078169 = 26000^2 + 3013^2 .

It is a cyclic number.

It is not a de Polignac number, because 685078169 - 2⁴ = 685078153 is a prime.

It is a super-2 number, since 2×685078169² = 938664195280785122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (685078469) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 342539084 + 342539085.

It is an arithmetic number, because the mean of its divisors is an integer number (342539085).

Almost surely, 2^685078169 is an apocalyptic number.

It is an amenable number.

685078169 is a deficient number, since it is larger than the sum of its proper divisors (1).

685078169 is an equidigital number, since it uses as much as digits as its factorization.

685078169 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 725760, while the sum is 50.

The square root of 685078169 is about 26173.9979559868. The cubic root of 685078169 is about 881.5495121692.

The spelling of 685078169 in words is "six hundred eighty-five million, seventy-eight thousand, one hundred sixty-nine".