686312891 has 8 divisors (see below), whose sum is σ = 760979568. Its totient is φ = 613692000.

The previous prime is 686312867. The next prime is 686312951. The reversal of 686312891 is 198213686.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 686312891 - 2⁶ = 686312827 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686312791) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 510740 + ... + 512081.

It is an arithmetic number, because the mean of its divisors is an integer number (95122446).

Almost surely, 2^686312891 is an apocalyptic number.

686312891 is a gapful number since it is divisible by the number (61) formed by its first and last digit.

686312891 is a deficient number, since it is larger than the sum of its proper divisors (74666677).

686312891 is a wasteful number, since it uses less digits than its factorization.

686312891 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1022893.

The product of its digits is 124416, while the sum is 44.

The square root of 686312891 is about 26197.5741434202. The cubic root of 686312891 is about 882.0788022859.

The spelling of 686312891 in words is "six hundred eighty-six million, three hundred twelve thousand, eight hundred ninety-one".