12181618 has 4 divisors (see below), whose sum is σ = 18272430. Its totient is φ = 6090808.

The previous prime is 12181613. The next prime is 12181619. The reversal of 12181618 is 81618121.

12181618 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 9199089 + 2982529 = 3033^2 + 1727^2 .

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 (12181613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3045403 + ... + 3045406.

Almost surely, 2^12181618 is an apocalyptic number.

12181618 is a deficient number, since it is larger than the sum of its proper divisors (6090812).

12181618 is an equidigital number, since it uses as much as digits as its factorization.

12181618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6090811.

The product of its digits is 768, while the sum is 28.

The square root of 12181618 is about 3490.2174717344. The cubic root of 12181618 is about 230.0920740369.

Adding to 12181618 its reverse (81618121), we get a palindrome (93799739).

The spelling of 12181618 in words is "twelve million, one hundred eighty-one thousand, six hundred eighteen".