686522 has 4 divisors (see below), whose sum is σ = 1029786. Its totient is φ = 343260.

The previous prime is 686519. The next prime is 686551. The reversal of 686522 is 225686.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 225686 = 2 ⋅112843.

It can be written as a sum of positive squares in only one way, i.e., 654481 + 32041 = 809^2 + 179^2 .

It is a nialpdrome in base 15.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171629 + ... + 171632.

2⁶⁸⁶⁵²² is an apocalyptic number.

686522 is a deficient number, since it is larger than the sum of its proper divisors (343264).

686522 is a wasteful number, since it uses less digits than its factorization.

686522 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343263.

The product of its digits is 5760, while the sum is 29.

The square root of 686522 is about 828.5662315108. The cubic root of 686522 is about 88.2168378478.

The spelling of 686522 in words is "six hundred eighty-six thousand, five hundred twenty-two".