309686 has 16 divisors (see below), whose sum is σ = 513744. Its totient is φ = 139104.

The previous prime is 309677. The next prime is 309707. The reversal of 309686 is 686903.

It is a happy number.

It is a Curzon number.

It is a plaindrome in base 8.

It is a congruent number.

It is an unprimeable number.

309686 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

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 7 ways as a sum of consecutive naturals, for example, 980 + ... + 1256.

It is an arithmetic number, because the mean of its divisors is an integer number (32109).

2³⁰⁹⁶⁸⁶ is an apocalyptic number.

309686 is a deficient number, since it is larger than the sum of its proper divisors (204058).

309686 is a wasteful number, since it uses less digits than its factorization.

309686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 335.

The product of its (nonzero) digits is 7776, while the sum is 32.

The square root of 309686 is about 556.4943845179. The cubic root of 309686 is about 67.6561360442.

It can be divided in two parts, 3096 and 86, that multiplied together give a square (266256 = 516²).

The spelling of 309686 in words is "three hundred nine thousand, six hundred eighty-six".