12216564 has 36 divisors (see below), whose sum is σ = 31118724. Its totient is φ = 4040832.

The previous prime is 12216559. The next prime is 12216577. The reversal of 12216564 is 46561221.

12216564 = 122² + 123² + ... + 337².

12216564 is a `hidden beast` number, since 1 + 2 + 2 + 1 + 656 + 4 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 6656400 + 5560164 = 2580^2 + 2358^2 .

It is a tau number, because it is divible by the number of its divisors (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 11 ways as a sum of consecutive naturals, for example, 3694 + ... + 6170.

It is an arithmetic number, because the mean of its divisors is an integer number (864409).

Almost surely, 2^12216564 is an apocalyptic number.

It is an amenable number.

12216564 is an abundant number, since it is smaller than the sum of its proper divisors (18902160).

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

12216564 is a wasteful number, since it uses less digits than its factorization.

12216564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2624 (or 2619 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 12216564 is about 3495.2201647393. The cubic root of 12216564 is about 230.3118894134.

Adding to 12216564 its reverse (46561221), we get a palindrome (58777785).

It can be divided in two parts, 1 and 2216564, that added together give a triangular number (2216565 = T₂₁₀₅).

The spelling of 12216564 in words is "twelve million, two hundred sixteen thousand, five hundred sixty-four".