18216618 has 16 divisors (see below), whose sum is σ = 41638080. Its totient is φ = 5204736.

The previous prime is 18216599. The next prime is 18216637. The reversal of 18216618 is 81661281.

It is an interprime number because it is at equal distance from previous prime (18216599) and next prime (18216637).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 216823 + ... + 216906.

It is an arithmetic number, because the mean of its divisors is an integer number (2602380).

Almost surely, 2^18216618 is an apocalyptic number.

18216618 is an abundant number, since it is smaller than the sum of its proper divisors (23421462).

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

18216618 is a wasteful number, since it uses less digits than its factorization.

18216618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 433741.

The product of its digits is 4608, while the sum is 33.

The square root of 18216618 is about 4268.0930167933. The cubic root of 18216618 is about 263.1212460276.

Adding to 18216618 its reverse (81661281), we get a palindrome (99877899).

The spelling of 18216618 in words is "eighteen million, two hundred sixteen thousand, six hundred eighteen".