686855131 has 4 divisors (see below), whose sum is σ = 727258392. Its totient is φ = 646451872.

The previous prime is 686855119. The next prime is 686855137. The reversal of 686855131 is 131558686.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-686855131 is a prime.

It is a super-2 number, since 2×686855131² = 943539941962054322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686855137) 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, 20201605 + ... + 20201638.

It is an arithmetic number, because the mean of its divisors is an integer number (181814598).

Almost surely, 2^686855131 is an apocalyptic number.

686855131 is a deficient number, since it is larger than the sum of its proper divisors (40403261).

686855131 is a wasteful number, since it uses less digits than its factorization.

686855131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 40403260.

The product of its digits is 172800, while the sum is 43.

The square root of 686855131 is about 26207.9211499119. The cubic root of 686855131 is about 882.3110445120.

The spelling of 686855131 in words is "six hundred eighty-six million, eight hundred fifty-five thousand, one hundred thirty-one".