685670399 has 4 divisors (see below), whose sum is σ = 692739264. Its totient is φ = 678601536.

The previous prime is 685670383. The next prime is 685670407. The reversal of 685670399 is 993076586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 993076586 = 2 ⋅496538293.

It is a cyclic number.

It is not a de Polignac number, because 685670399 - 2⁴ = 685670383 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 685670399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685670099) 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 in 3 ways as a sum of consecutive naturals, for example, 3534287 + ... + 3534480.

It is an arithmetic number, because the mean of its divisors is an integer number (173184816).

Almost surely, 2^685670399 is an apocalyptic number.

685670399 is a deficient number, since it is larger than the sum of its proper divisors (7068865).

685670399 is an equidigital number, since it uses as much as digits as its factorization.

685670399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7068864.

The product of its (nonzero) digits is 2449440, while the sum is 53.

The square root of 685670399 is about 26185.3088391182. The cubic root of 685670399 is about 881.8034635781.

The spelling of 685670399 in words is "six hundred eighty-five million, six hundred seventy thousand, three hundred ninety-nine".