2809321 has 4 divisors (see below), whose sum is σ = 2957200. Its totient is φ = 2661444.

The previous prime is 2809309. The next prime is 2809327. The reversal of 2809321 is 1239082.

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 not a de Polignac number, because 2809321 - 2⁹ = 2808809 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2809327) 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, 73911 + ... + 73948.

It is an arithmetic number, because the mean of its divisors is an integer number (739300).

2^2809321 is an apocalyptic number.

It is an amenable number.

2809321 is a deficient number, since it is larger than the sum of its proper divisors (147879).

2809321 is a wasteful number, since it uses less digits than its factorization.

2809321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147878.

The product of its (nonzero) digits is 864, while the sum is 25.

The square root of 2809321 is about 1676.1029204676. The cubic root of 2809321 is about 141.1022011077.

The spelling of 2809321 in words is "two million, eight hundred nine thousand, three hundred twenty-one".