686855871 has 48 divisors (see below), whose sum is σ = 1161072640. Its totient is φ = 387478080.

The previous prime is 686855867. The next prime is 686855881. The reversal of 686855871 is 178558686.

686855871 is a `hidden beast` number, since 6 + 86 + 8 + 558 + 7 + 1 = 666.

It is not a de Polignac number, because 686855871 - 2² = 686855867 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686855801) 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 47 ways as a sum of consecutive naturals, for example, 63930 + ... + 73896.

Almost surely, 2^686855871 is an apocalyptic number.

686855871 is a deficient number, since it is larger than the sum of its proper divisors (474216769).

686855871 is a wasteful number, since it uses less digits than its factorization.

686855871 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10036 (or 10033 counting only the distinct ones).

The product of its digits is 3225600, while the sum is 54.

The square root of 686855871 is about 26207.9352677772. The cubic root of 686855871 is about 882.3113613716.

The spelling of 686855871 in words is "six hundred eighty-six million, eight hundred fifty-five thousand, eight hundred seventy-one".