16561518 has 16 divisors (see below), whose sum is σ = 34563456. Its totient is φ = 5280440.

The previous prime is 16561513. The next prime is 16561543. The reversal of 16561518 is 81516561.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16561511) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 59868 + ... + 60143.

It is an arithmetic number, because the mean of its divisors is an integer number (2160216).

Almost surely, 2^16561518 is an apocalyptic number.

16561518 is an abundant number, since it is smaller than the sum of its proper divisors (18001938).

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

16561518 is a wasteful number, since it uses less digits than its factorization.

16561518 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120039.

The product of its digits is 7200, while the sum is 33.

The square root of 16561518 is about 4069.5844996756. The cubic root of 16561518 is about 254.8981677209.

The spelling of 16561518 in words is "sixteen million, five hundred sixty-one thousand, five hundred eighteen".