16665564 has 12 divisors (see below), whose sum is σ = 38886344. Its totient is φ = 5555184.

The previous prime is 16665563. The next prime is 16665581. The reversal of 16665564 is 46556661.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16665563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 694387 + ... + 694410.

Almost surely, 2^16665564 is an apocalyptic number.

It is an amenable number.

16665564 is an abundant number, since it is smaller than the sum of its proper divisors (22220780).

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

16665564 is a wasteful number, since it uses less digits than its factorization.

16665564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1388804 (or 1388802 counting only the distinct ones).

The product of its digits is 129600, while the sum is 39.

The square root of 16665564 is about 4082.3478538704. The cubic root of 16665564 is about 255.4308441145.

The spelling of 16665564 in words is "sixteen million, six hundred sixty-five thousand, five hundred sixty-four".