685867871 has 24 divisors (see below), whose sum is σ = 787810464. Its totient is φ = 593438400.

The previous prime is 685867849. The next prime is 685867879. The reversal of 685867871 is 178768586.

685867871 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 685867871 - 2¹⁸ = 685605727 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685867879) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 473270 + ... + 474716.

It is an arithmetic number, because the mean of its divisors is an integer number (32825436).

Almost surely, 2^685867871 is an apocalyptic number.

685867871 is a deficient number, since it is larger than the sum of its proper divisors (101942593).

685867871 is a wasteful number, since it uses less digits than its factorization.

685867871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1599 (or 1580 counting only the distinct ones).

The product of its digits is 4515840, while the sum is 56.

The square root of 685867871 is about 26189.0792316187. The cubic root of 685867871 is about 881.8881081245. Note that the first 3 decimals are identical.

The spelling of 685867871 in words is "six hundred eighty-five million, eight hundred sixty-seven thousand, eight hundred seventy-one".