18686818 has 16 divisors (see below), whose sum is σ = 28690560. Its totient is φ = 9126000.

The previous prime is 18686807. The next prime is 18686819. The reversal of 18686818 is 81868681.

It is not an unprimeable number, because it can be changed into a prime (18686819) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15373 + ... + 16543.

It is an arithmetic number, because the mean of its divisors is an integer number (1793160).

Almost surely, 2^18686818 is an apocalyptic number.

18686818 is a deficient number, since it is larger than the sum of its proper divisors (10003742).

18686818 is a wasteful number, since it uses less digits than its factorization.

18686818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1353.

The product of its digits is 147456, while the sum is 46.

The square root of 18686818 is about 4322.8252335712. The cubic root of 18686818 is about 265.3659025167.

It can be divided in two parts, 1868681 and 8, that added together give a square (1868689 = 1367²).

The spelling of 18686818 in words is "eighteen million, six hundred eighty-six thousand, eight hundred eighteen".