6561541539 has 24 divisors (see below), whose sum is σ = 11307874320. Its totient is φ = 3749451552.

The previous prime is 6561541531. The next prime is 6561541541. The reversal of 6561541539 is 9351451656.

6561541539 is a `hidden beast` number, since 6 + 5 + 61 + 54 + 1 + 539 = 666.

It is not a de Polignac number, because 6561541539 - 2³ = 6561541531 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 6561541494 and 6561541503.

It is not an unprimeable number, because it can be changed into a prime (6561541531) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2478474 + ... + 2481119.

It is an arithmetic number, because the mean of its divisors is an integer number (471161430).

Almost surely, 2^6561541539 is an apocalyptic number.

6561541539 is a deficient number, since it is larger than the sum of its proper divisors (4746332781).

6561541539 is a wasteful number, since it uses less digits than its factorization.

6561541539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4959616 (or 4959603 counting only the distinct ones).

The product of its digits is 486000, while the sum is 45.

The square root of 6561541539 is about 81003.3427643576. The cubic root of 6561541539 is about 1872.1269458003.

The spelling of 6561541539 in words is "six billion, five hundred sixty-one million, five hundred forty-one thousand, five hundred thirty-nine".