16320509 has 4 divisors (see below), whose sum is σ = 16334304. Its totient is φ = 16306716.

The previous prime is 16320481. The next prime is 16320517. The reversal of 16320509 is 90502361.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 16320509 - 2⁸ = 16320253 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16320529) 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, 4937 + ... + 7550.

It is an arithmetic number, because the mean of its divisors is an integer number (4083576).

Almost surely, 2^16320509 is an apocalyptic number.

It is an amenable number.

16320509 is a deficient number, since it is larger than the sum of its proper divisors (13795).

16320509 is a wasteful number, since it uses less digits than its factorization.

16320509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13794.

The product of its (nonzero) digits is 1620, while the sum is 26.

The square root of 16320509 is about 4039.8649729911. The cubic root of 16320509 is about 253.6556652262.

The spelling of 16320509 in words is "sixteen million, three hundred twenty thousand, five hundred nine".