6661564 has 24 divisors (see below), whose sum is σ = 14348768. Its totient is φ = 2635200.

The previous prime is 6661553. The next prime is 6661583. The reversal of 6661564 is 4651666.

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 7 ways as a sum of consecutive naturals, for example, 8787 + ... + 9514.

Almost surely, 2^6661564 is an apocalyptic number.

It is an amenable number.

6661564 is an abundant number, since it is smaller than the sum of its proper divisors (7687204).

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

6661564 is a wasteful number, since it uses less digits than its factorization.

6661564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18325 (or 18323 counting only the distinct ones).

The product of its digits is 25920, while the sum is 34.

The square root of 6661564 is about 2581.0005811700. Note that the first 3 decimals coincide. The cubic root of 6661564 is about 188.1591755883.

It can be divided in two parts, 6661 and 564, that added together give a square (7225 = 85²).

The spelling of 6661564 in words is "six million, six hundred sixty-one thousand, five hundred sixty-four".