309906 has 20 divisors (see below), whose sum is σ = 694782. Its totient is φ = 103248.

The previous prime is 309899. The next prime is 309929. The reversal of 309906 is 609903.

309906 is nontrivially palindromic in base 7.

It can be written as a sum of positive squares in only one way, i.e., 210681 + 99225 = 459^2 + 315^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a nialpdrome in base 9.

It is a self number, because there is not a number n which added to its sum of digits gives 309906.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 309906.

It is an unprimeable number.

309906 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 795 + ... + 1118.

2³⁰⁹⁹⁰⁶ is an apocalyptic number.

309906 is an abundant number, since it is smaller than the sum of its proper divisors (384876).

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

309906 is a wasteful number, since it uses less digits than its factorization.

309906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1927 (or 1918 counting only the distinct ones).

The product of its (nonzero) digits is 1458, while the sum is 27.

The square root of 309906 is about 556.6920153909. The cubic root of 309906 is about 67.6721531570.

Adding to 309906 its product of nonzero digits (1458), we get a square (311364 = 558²).

The spelling of 309906 in words is "three hundred nine thousand, nine hundred six".