686549 has 4 divisors (see below), whose sum is σ = 696864. Its totient is φ = 676236.

The previous prime is 686519. The next prime is 686551. The reversal of 686549 is 945686.

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 686549 - 2⁸ = 686293 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 (686519) 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, 5057 + ... + 5190.

It is an arithmetic number, because the mean of its divisors is an integer number (174216).

2⁶⁸⁶⁵⁴⁹ is an apocalyptic number.

It is an amenable number.

686549 is a deficient number, since it is larger than the sum of its proper divisors (10315).

686549 is a wasteful number, since it uses less digits than its factorization.

686549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10314.

The product of its digits is 51840, while the sum is 38.

The square root of 686549 is about 828.5825245562. The cubic root of 686549 is about 88.2179943164.

The spelling of 686549 in words is "six hundred eighty-six thousand, five hundred forty-nine".