2161321 has 4 divisors (see below), whose sum is σ = 2173444. Its totient is φ = 2149200.

The previous prime is 2161319. The next prime is 2161331. The reversal of 2161321 is 1231612.

2161321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 215296 + 1946025 = 464^2 + 1395^2 .

It is a cyclic number.

It is not a de Polignac number, because 2161321 - 2¹ = 2161319 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2161295 and 2161304.

It is not an unprimeable number, because it can be changed into a prime (2161301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5790 + ... + 6151.

It is an arithmetic number, because the mean of its divisors is an integer number (543361).

2^2161321 is an apocalyptic number.

It is an amenable number.

2161321 is a deficient number, since it is larger than the sum of its proper divisors (12123).

2161321 is a wasteful number, since it uses less digits than its factorization.

2161321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12122.

The product of its digits is 72, while the sum is 16.

The square root of 2161321 is about 1470.1431903049. The cubic root of 2161321 is about 129.2924279597.

Adding to 2161321 its reverse (1231612), we get a palindrome (3392933).

The spelling of 2161321 in words is "two million, one hundred sixty-one thousand, three hundred twenty-one".