18663668 has 6 divisors (see below), whose sum is σ = 32661426. Its totient is φ = 9331832.

The previous prime is 18663661. The next prime is 18663683. The reversal of 18663668 is 86636681.

It can be written as a sum of positive squares in only one way, i.e., 9972964 + 8690704 = 3158^2 + 2948^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18663661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2332955 + ... + 2332962.

It is an arithmetic number, because the mean of its divisors is an integer number (5443571).

Almost surely, 2^18663668 is an apocalyptic number.

It is an amenable number.

18663668 is a deficient number, since it is larger than the sum of its proper divisors (13997758).

18663668 is a wasteful number, since it uses less digits than its factorization.

18663668 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4665921 (or 4665919 counting only the distinct ones).

The product of its digits is 248832, while the sum is 44.

The square root of 18663668 is about 4320.1467567665. The cubic root of 18663668 is about 265.2562751631.

The spelling of 18663668 in words is "eighteen million, six hundred sixty-three thousand, six hundred sixty-eight".