2121360565 has 4 divisors (see below), whose sum is σ = 2545632684. Its totient is φ = 1697088448.

The previous prime is 2121360551. The next prime is 2121360569. The reversal of 2121360565 is 5650631212.

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 1478940849 + 642419716 = 38457^2 + 25346^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121360565 - 2²¹ = 2119263413 is a prime.

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121360569) 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, 212136052 + ... + 212136061.

It is an arithmetic number, because the mean of its divisors is an integer number (636408171).

Almost surely, 2^2121360565 is an apocalyptic number.

It is an amenable number.

2121360565 is a deficient number, since it is larger than the sum of its proper divisors (424272119).

2121360565 is an equidigital number, since it uses as much as digits as its factorization.

2121360565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424272118.

The product of its (nonzero) digits is 10800, while the sum is 31.

The square root of 2121360565 is about 46058.2301548811. The cubic root of 2121360565 is about 1284.9064141748.

Adding to 2121360565 its reverse (5650631212), we get a palindrome (7771991777).

The spelling of 2121360565 in words is "two billion, one hundred twenty-one million, three hundred sixty thousand, five hundred sixty-five".