6561004521 has 4 divisors (see below), whose sum is σ = 8748006032. Its totient is φ = 4374003012.

The previous prime is 6561004481. The next prime is 6561004561. The reversal of 6561004521 is 1254001656.

6561004521 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (6561004481) and next prime (6561004561).

It is not a de Polignac number, because 6561004521 - 2¹⁰ = 6561003497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6561004561) 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, 1093500751 + ... + 1093500756.

It is an arithmetic number, because the mean of its divisors is an integer number (2187001508).

Almost surely, 2^6561004521 is an apocalyptic number.

It is an amenable number.

6561004521 is a deficient number, since it is larger than the sum of its proper divisors (2187001511).

6561004521 is a wasteful number, since it uses less digits than its factorization.

6561004521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2187001510.

The product of its (nonzero) digits is 7200, while the sum is 30.

The square root of 6561004521 is about 81000.0279074026. The cubic root of 6561004521 is about 1872.0758707447.

The spelling of 6561004521 in words is "six billion, five hundred sixty-one million, four thousand, five hundred twenty-one".