686870861 has 4 divisors (see below), whose sum is σ = 698512800. Its totient is φ = 675228924.

The previous prime is 686870857. The next prime is 686870867. The reversal of 686870861 is 168078686.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 686870861 - 2² = 686870857 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686870867) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5820881 + ... + 5820998.

It is an arithmetic number, because the mean of its divisors is an integer number (174628200).

Almost surely, 2^686870861 is an apocalyptic number.

It is an amenable number.

686870861 is a deficient number, since it is larger than the sum of its proper divisors (11641939).

686870861 is a wasteful number, since it uses less digits than its factorization.

686870861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11641938.

The product of its (nonzero) digits is 774144, while the sum is 50.

The square root of 686870861 is about 26208.2212483030. The cubic root of 686870861 is about 882.3177798706.

The spelling of 686870861 in words is "six hundred eighty-six million, eight hundred seventy thousand, eight hundred sixty-one".