2121501565 has 4 divisors (see below), whose sum is σ = 2545801884. Its totient is φ = 1697201248.

The previous prime is 2121501559. The next prime is 2121501589. The reversal of 2121501565 is 5651051212.

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 1405725049 + 715776516 = 37493^2 + 26754^2 .

It is a cyclic number.

It is not a de Polignac number, because 2121501565 - 2⁵ = 2121501533 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 212150152 + ... + 212150161.

It is an arithmetic number, because the mean of its divisors is an integer number (636450471).

Almost surely, 2^2121501565 is an apocalyptic number.

It is an amenable number.

2121501565 is a deficient number, since it is larger than the sum of its proper divisors (424300319).

2121501565 is an equidigital number, since it uses as much as digits as its factorization.

2121501565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 424300318.

The product of its (nonzero) digits is 3000, while the sum is 28.

The square root of 2121501565 is about 46059.7608005079. The cubic root of 2121501565 is about 1284.9348814069.

Adding to 2121501565 its reverse (5651051212), we get a palindrome (7772552777).

The spelling of 2121501565 in words is "two billion, one hundred twenty-one million, five hundred one thousand, five hundred sixty-five".