2165313121 has 4 divisors (see below), whose sum is σ = 2165476500. Its totient is φ = 2165149744.

The previous prime is 2165313109. The next prime is 2165313181. The reversal of 2165313121 is 1213135612.

It is a happy number.

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 843263521 + 1322049600 = 29039^2 + 36360^2 .

It is a cyclic number.

It is not a de Polignac number, because 2165313121 - 2⁹ = 2165312609 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2165313181) 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, 59866 + ... + 88963.

It is an arithmetic number, because the mean of its divisors is an integer number (541369125).

Almost surely, 2^2165313121 is an apocalyptic number.

It is an amenable number.

2165313121 is a deficient number, since it is larger than the sum of its proper divisors (163379).

2165313121 is a wasteful number, since it uses less digits than its factorization.

2165313121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 163378.

The product of its digits is 1080, while the sum is 25.

The square root of 2165313121 is about 46532.9251283433. The cubic root of 2165313121 is about 1293.7198324906.

Adding to 2165313121 its reverse (1213135612), we get a palindrome (3378448733).

The spelling of 2165313121 in words is "two billion, one hundred sixty-five million, three hundred thirteen thousand, one hundred twenty-one".