685356871 has 4 divisors (see below), whose sum is σ = 693057600. Its totient is φ = 677656144.

The previous prime is 685356863. The next prime is 685356877. The reversal of 685356871 is 178653586.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 178653586 = 2 ⋅89326793.

It is a cyclic number.

It is not a de Polignac number, because 685356871 - 2³ = 685356863 is a prime.

It is a Smith number, since the sum of its digits (49) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685356877) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3850231 + ... + 3850408.

It is an arithmetic number, because the mean of its divisors is an integer number (173264400).

Almost surely, 2^685356871 is an apocalyptic number.

685356871 is a deficient number, since it is larger than the sum of its proper divisors (7700729).

685356871 is an equidigital number, since it uses as much as digits as its factorization.

685356871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7700728.

The product of its digits is 1209600, while the sum is 49.

The square root of 685356871 is about 26179.3214388761. The cubic root of 685356871 is about 881.6690393092.

The spelling of 685356871 in words is "six hundred eighty-five million, three hundred fifty-six thousand, eight hundred seventy-one".