685855361 has 4 divisors (see below), whose sum is σ = 726199812. Its totient is φ = 645510912.

The previous prime is 685855333. The next prime is 685855397. The reversal of 685855361 is 163558586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 163558586 = 2 ⋅81779293.

It can be written as a sum of positive squares in 2 ways, for example, as 593214736 + 92640625 = 24356^2 + 9625^2 .

It is a cyclic number.

It is not a de Polignac number, because 685855361 - 2¹⁴ = 685838977 is a prime.

It is not an unprimeable number, because it can be changed into a prime (685855301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 20172200 + ... + 20172233.

It is an arithmetic number, because the mean of its divisors is an integer number (181549953).

Almost surely, 2^685855361 is an apocalyptic number.

It is an amenable number.

685855361 is a deficient number, since it is larger than the sum of its proper divisors (40344451).

685855361 is a wasteful number, since it uses less digits than its factorization.

685855361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 40344450.

The product of its digits is 864000, while the sum is 47.

The square root of 685855361 is about 26188.8403905175. The cubic root of 685855361 is about 881.8827463108.

The spelling of 685855361 in words is "six hundred eighty-five million, eight hundred fifty-five thousand, three hundred sixty-one".