16561618 has 8 divisors (see below), whose sum is σ = 24886512. Its totient is φ = 8266116.

The previous prime is 16561613. The next prime is 16561627. The reversal of 16561618 is 81616561.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an alternating number because its digits alternate between odd and even.

It is not an unprimeable number, because it can be changed into a prime (16561613) 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, 5880 + ... + 8227.

It is an arithmetic number, because the mean of its divisors is an integer number (3110814).

Almost surely, 2^16561618 is an apocalyptic number.

16561618 is a deficient number, since it is larger than the sum of its proper divisors (8324894).

16561618 is a wasteful number, since it uses less digits than its factorization.

16561618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14696.

The product of its digits is 8640, while the sum is 34.

The square root of 16561618 is about 4069.5967859236. The cubic root of 16561618 is about 254.8986807529.

The spelling of 16561618 in words is "sixteen million, five hundred sixty-one thousand, six hundred eighteen".