6645564 has 84 divisors (see below), whose sum is σ = 18178776. Its totient is φ = 2122848.

The previous prime is 6645557. The next prime is 6645571. The reversal of 6645564 is 4655466.

It is a happy number.

6645564 is a `hidden beast` number, since 6 + 645 + 5 + 6 + 4 = 666.

It is an interprime number because it is at equal distance from previous prime (6645557) and next prime (6645571).

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 27 ways as a sum of consecutive naturals, for example, 125362 + ... + 125414.

It is an arithmetic number, because the mean of its divisors is an integer number (216414).

Almost surely, 2^6645564 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6645564, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9089388).

6645564 is an abundant number, since it is smaller than the sum of its proper divisors (11533212).

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

6645564 is a wasteful number, since it uses less digits than its factorization.

6645564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 118 (or 101 counting only the distinct ones).

The product of its digits is 86400, while the sum is 36.

The square root of 6645564 is about 2577.8991446525. The cubic root of 6645564 is about 188.0084121783.

The spelling of 6645564 in words is "six million, six hundred forty-five thousand, five hundred sixty-four".