309666 has 32 divisors (see below), whose sum is σ = 724608. Its totient is φ = 86400.

The previous prime is 309637. The next prime is 309667. The reversal of 309666 is 666903.

It is not an unprimeable number, because it can be changed into a prime (309667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3016 + ... + 3116.

It is an arithmetic number, because the mean of its divisors is an integer number (22644).

2³⁰⁹⁶⁶⁶ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 309666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (362304).

309666 is an abundant number, since it is smaller than the sum of its proper divisors (414942).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

309666 is a wasteful number, since it uses less digits than its factorization.

309666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 186.

The product of its (nonzero) digits is 5832, while the sum is 30.

The square root of 309666 is about 556.4764145945. The cubic root of 309666 is about 67.6546795670.

The spelling of 309666 in words is "three hundred nine thousand, six hundred sixty-six".