3128809 has 4 divisors (see below), whose sum is σ = 3201616. Its totient is φ = 3056004.

The previous prime is 3128803. The next prime is 3128813. The reversal of 3128809 is 9088213.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 3128809 - 2¹⁷ = 2997737 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3128803) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36339 + ... + 36424.

It is an arithmetic number, because the mean of its divisors is an integer number (800404).

Almost surely, 2^3128809 is an apocalyptic number.

It is an amenable number.

3128809 is a deficient number, since it is larger than the sum of its proper divisors (72807).

3128809 is an equidigital number, since it uses as much as digits as its factorization.

3128809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72806.

The product of its (nonzero) digits is 3456, while the sum is 31.

The square root of 3128809 is about 1768.8439727687. The cubic root of 3128809 is about 146.2602632386.

The spelling of 3128809 in words is "three million, one hundred twenty-eight thousand, eight hundred nine".