6525121221 has 6 divisors (see below), whose sum is σ = 9425175110. Its totient is φ = 4350080808.

The previous prime is 6525121219. The next prime is 6525121231. The reversal of 6525121221 is 1221215256.

6525121221 is a `hidden beast` number, since 6 + 525 + 12 + 122 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 6338388996 + 186732225 = 79614^2 + 13665^2 .

It is not a de Polignac number, because 6525121221 - 2¹ = 6525121219 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6525121201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 362506726 + ... + 362506743.

Almost surely, 2^6525121221 is an apocalyptic number.

It is an amenable number.

6525121221 is a deficient number, since it is larger than the sum of its proper divisors (2900053889).

6525121221 is a wasteful number, since it uses less digits than its factorization.

6525121221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 725013475 (or 725013472 counting only the distinct ones).

The product of its digits is 2400, while the sum is 27.

The square root of 6525121221 is about 80778.2224426856. Note that the first 3 decimals coincide. The cubic root of 6525121221 is about 1868.6567246040.

Adding to 6525121221 its reverse (1221215256), we get a palindrome (7746336477).

The spelling of 6525121221 in words is "six billion, five hundred twenty-five million, one hundred twenty-one thousand, two hundred twenty-one".