18161618 has 8 divisors (see below), whose sum is σ = 27512460. Its totient is φ = 8990800.

The previous prime is 18161581. The next prime is 18161621. The reversal of 18161618 is 81616181.

It can be written as a sum of positive squares in 2 ways, for example, as 18037009 + 124609 = 4247^2 + 353^2 .

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 an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 44753 + ... + 45156.

Almost surely, 2^18161618 is an apocalyptic number.

18161618 is a deficient number, since it is larger than the sum of its proper divisors (9350842).

18161618 is a wasteful number, since it uses less digits than its factorization.

18161618 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90012.

The product of its digits is 2304, while the sum is 32.

The square root of 18161618 is about 4261.6449875606. The cubic root of 18161618 is about 262.8561719910.

Adding to 18161618 its reverse (81616181), we get a palindrome (99777799).

The spelling of 18161618 in words is "eighteen million, one hundred sixty-one thousand, six hundred eighteen".