11815618 has 4 divisors (see below), whose sum is σ = 17723430. Its totient is φ = 5907808.

The previous prime is 11815613. The next prime is 11815621. The reversal of 11815618 is 81651811.

It is a happy number.

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., 11744329 + 71289 = 3427^2 + 267^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 11815618.

It is not an unprimeable number, because it can be changed into a prime (11815613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2953903 + ... + 2953906.

Almost surely, 2^11815618 is an apocalyptic number.

11815618 is a deficient number, since it is larger than the sum of its proper divisors (5907812).

11815618 is an equidigital number, since it uses as much as digits as its factorization.

11815618 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5907811.

The product of its digits is 1920, while the sum is 31.

The square root of 11815618 is about 3437.3853435424. The cubic root of 11815618 is about 227.7642094017.

It can be divided in two parts, 1181561 and 8, that added together give a square (1181569 = 1087²).

The spelling of 11815618 in words is "eleven million, eight hundred fifteen thousand, six hundred eighteen".