3128309 has 4 divisors (see below), whose sum is σ = 3131916. Its totient is φ = 3124704.

The previous prime is 3128291. The next prime is 3128311. The reversal of 3128309 is 9038213.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 9038213 = 43 ⋅210191.

It can be written as a sum of positive squares in 2 ways, for example, as 1747684 + 1380625 = 1322^2 + 1175^2 .

It is a cyclic number.

It is not a de Polignac number, because 3128309 - 2⁸ = 3128053 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 (3128329) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 377 + ... + 2529.

It is an arithmetic number, because the mean of its divisors is an integer number (782979).

Almost surely, 2^3128309 is an apocalyptic number.

It is an amenable number.

3128309 is a deficient number, since it is larger than the sum of its proper divisors (3607).

3128309 is a wasteful number, since it uses less digits than its factorization.

3128309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3606.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 3128309 is about 1768.7026318746. The cubic root of 3128309 is about 146.2524717726.

The spelling of 3128309 in words is "three million, one hundred twenty-eight thousand, three hundred nine".