18666418 has 4 divisors (see below), whose sum is σ = 27999630. Its totient is φ = 9333208.

The previous prime is 18666413. The next prime is 18666419. The reversal of 18666418 is 81466681.

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., 18636489 + 29929 = 4317^2 + 173^2 .

It is not an unprimeable number, because it can be changed into a prime (18666413) by changing a digit.

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 as a sum of consecutive naturals, namely, 4666603 + ... + 4666606.

Almost surely, 2^18666418 is an apocalyptic number.

18666418 is a deficient number, since it is larger than the sum of its proper divisors (9333212).

18666418 is an equidigital number, since it uses as much as digits as its factorization.

18666418 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9333211.

The product of its digits is 55296, while the sum is 40.

The square root of 18666418 is about 4320.4650212680. The cubic root of 18666418 is about 265.2693025939.

The spelling of 18666418 in words is "eighteen million, six hundred sixty-six thousand, four hundred eighteen".