6561881652 has 24 divisors (see below), whose sum is σ = 15365552832. Its totient is φ = 2179508800.

The previous prime is 6561881639. The next prime is 6561881653. The reversal of 6561881652 is 2561881656.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561881653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 969624 + ... + 976367.

It is an arithmetic number, because the mean of its divisors is an integer number (640231368).

Almost surely, 2^6561881652 is an apocalyptic number.

It is an amenable number.

6561881652 is an abundant number, since it is smaller than the sum of its proper divisors (8803671180).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6561881652 is a wasteful number, since it uses less digits than its factorization.

6561881652 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1946279 (or 1946277 counting only the distinct ones).

The product of its digits is 691200, while the sum is 48.

The square root of 6561881652 is about 81005.4421134778. The cubic root of 6561881652 is about 1872.1592920464.

The spelling of 6561881652 in words is "six billion, five hundred sixty-one million, eight hundred eighty-one thousand, six hundred fifty-two".