6561242505 has 96 divisors (see below), whose sum is σ = 12011231232. Its totient is φ = 3309465600.

The previous prime is 6561242503. The next prime is 6561242521. The reversal of 6561242505 is 5052421656.

6561242505 is a `hidden beast` number, since 6 + 561 + 2 + 42 + 50 + 5 = 666.

It is not a de Polignac number, because 6561242505 - 2¹ = 6561242503 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6561242505.

It is not an unprimeable number, because it can be changed into a prime (6561242503) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 15152769 + ... + 15153201.

It is an arithmetic number, because the mean of its divisors is an integer number (125116992).

Almost surely, 2^6561242505 is an apocalyptic number.

It is an amenable number.

6561242505 is a deficient number, since it is larger than the sum of its proper divisors (5449988727).

6561242505 is a wasteful number, since it uses less digits than its factorization.

6561242505 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 719 (or 716 counting only the distinct ones).

The product of its (nonzero) digits is 72000, while the sum is 36.

The square root of 6561242505 is about 81001.4969306123. The cubic root of 6561242505 is about 1872.0985054249.

The spelling of 6561242505 in words is "six billion, five hundred sixty-one million, two hundred forty-two thousand, five hundred five".