6561684 has 36 divisors (see below), whose sum is σ = 16743636. Its totient is φ = 2166528.

The previous prime is 6561683. The next prime is 6561697. The reversal of 6561684 is 4861656.

It can be written as a sum of positive squares in 2 ways, for example, as 1633284 + 4928400 = 1278^2 + 2220^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6561683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3262 + ... + 4874.

It is an arithmetic number, because the mean of its divisors is an integer number (465101).

Almost surely, 2^6561684 is an apocalyptic number.

It is an amenable number.

6561684 is an abundant number, since it is smaller than the sum of its proper divisors (10181952).

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

6561684 is a wasteful number, since it uses less digits than its factorization.

6561684 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1736 (or 1731 counting only the distinct ones).

The product of its digits is 34560, while the sum is 36.

The square root of 6561684 is about 2561.5784196468. The cubic root of 6561684 is about 187.2140494606.

The spelling of 6561684 in words is "six million, five hundred sixty-one thousand, six hundred eighty-four".