686291 has 4 divisors (see below), whose sum is σ = 690432. Its totient is φ = 682152.

The previous prime is 686269. The next prime is 686293. The reversal of 686291 is 192686.

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

It is a cyclic number.

It is not a de Polignac number, because 686291 - 2¹⁸ = 424147 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (686293) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1811 + ... + 2156.

It is an arithmetic number, because the mean of its divisors is an integer number (172608).

2⁶⁸⁶²⁹¹ is an apocalyptic number.

686291 is a deficient number, since it is larger than the sum of its proper divisors (4141).

686291 is a wasteful number, since it uses less digits than its factorization.

686291 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4140.

The product of its digits is 5184, while the sum is 32.

The square root of 686291 is about 828.4268223567. The cubic root of 686291 is about 88.2069423768.

The spelling of 686291 in words is "six hundred eighty-six thousand, two hundred ninety-one".