686348991 has 8 divisors (see below), whose sum is σ = 1016813360. Its totient is φ = 457565976.

The previous prime is 686348969. The next prime is 686349017. The reversal of 686348991 is 199843686.

It is not a de Polignac number, because 686348991 - 2¹¹ = 686346943 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 (686348921) 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, 12710140 + ... + 12710193.

It is an arithmetic number, because the mean of its divisors is an integer number (127101670).

Almost surely, 2^686348991 is an apocalyptic number.

686348991 is a deficient number, since it is larger than the sum of its proper divisors (330464369).

686348991 is a wasteful number, since it uses less digits than its factorization.

686348991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 25420342 (or 25420336 counting only the distinct ones).

The product of its digits is 2239488, while the sum is 54.

The square root of 686348991 is about 26198.2631294519. The cubic root of 686348991 is about 882.0942677715.

The spelling of 686348991 in words is "six hundred eighty-six million, three hundred forty-eight thousand, nine hundred ninety-one".