16564009 has 24 divisors (see below), whose sum is σ = 21340800. Its totient is φ = 12710880.

The previous prime is 16564007. The next prime is 16564021. The reversal of 16564009 is 90046561.

It is not a de Polignac number, because 16564009 - 2¹ = 16564007 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16564007) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42387 + ... + 42775.

It is an arithmetic number, because the mean of its divisors is an integer number (889200).

Almost surely, 2^16564009 is an apocalyptic number.

It is an amenable number.

16564009 is a deficient number, since it is larger than the sum of its proper divisors (4776791).

16564009 is a wasteful number, since it uses less digits than its factorization.

16564009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493 (or 486 counting only the distinct ones).

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 16564009 is about 4069.8905390686. The cubic root of 16564009 is about 254.9109467327.

It can be divided in two parts, 1656 and 4009, that added together give a palindrome (5665).

The spelling of 16564009 in words is "sixteen million, five hundred sixty-four thousand, nine".