3201661521 has 24 divisors (see below), whose sum is σ = 4694810120. Its totient is φ = 2102132736.

The previous prime is 3201661511. The next prime is 3201661537. The reversal of 3201661521 is 1251661023.

3201661521 is a `hidden beast` number, since 3 + 20 + 1 + 6 + 615 + 21 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 271063296 + 2930598225 = 16464^2 + 54135^2 .

It is not a de Polignac number, because 3201661521 - 2¹¹ = 3201659473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (3201661501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 502065 + ... + 508401.

Almost surely, 2^3201661521 is an apocalyptic number.

It is an amenable number.

3201661521 is a deficient number, since it is larger than the sum of its proper divisors (1493148599).

3201661521 is a wasteful number, since it uses less digits than its factorization.

3201661521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7185 (or 7182 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 3201661521 is about 56583.2264986718. The cubic root of 3201661521 is about 1473.8676009810.

The spelling of 3201661521 in words is "three billion, two hundred one million, six hundred sixty-one thousand, five hundred twenty-one".