2131528221 has 12 divisors (see below), whose sum is σ = 3259984572. Its totient is φ = 1337429376.

The previous prime is 2131528211. The next prime is 2131528237. The reversal of 2131528221 is 1228251312.

2131528221 is a `hidden beast` number, since 2 + 131 + 528 + 2 + 2 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 1505828025 + 625700196 = 38805^2 + 25014^2 .

It is not a de Polignac number, because 2131528221 - 2⁷ = 2131528093 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2131528211) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 6965626 + ... + 6965931.

It is an arithmetic number, because the mean of its divisors is an integer number (271665381).

Almost surely, 2^2131528221 is an apocalyptic number.

It is an amenable number.

2131528221 is a deficient number, since it is larger than the sum of its proper divisors (1128456351).

2131528221 is a wasteful number, since it uses less digits than its factorization.

2131528221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13931580 (or 13931577 counting only the distinct ones).

The product of its digits is 1920, while the sum is 27.

The square root of 2131528221 is about 46168.4764855848. The cubic root of 2131528221 is about 1286.9559901853.

Adding to 2131528221 its reverse (1228251312), we get a palindrome (3359779533).

The spelling of 2131528221 in words is "two billion, one hundred thirty-one million, five hundred twenty-eight thousand, two hundred twenty-one".