18663666 has 32 divisors (see below), whose sum is σ = 43008000. Its totient is φ = 5288976.

The previous prime is 18663661. The next prime is 18663683. The reversal of 18663666 is 66636681.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a Curzon 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 in 15 ways as a sum of consecutive naturals, for example, 3585 + ... + 7083.

It is an arithmetic number, because the mean of its divisors is an integer number (1344000).

Almost surely, 2^18663666 is an apocalyptic number.

18663666 is an abundant number, since it is smaller than the sum of its proper divisors (24344334).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18663666 is a wasteful number, since it uses less digits than its factorization.

18663666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3638.

The product of its digits is 186624, while the sum is 42.

The square root of 18663666 is about 4320.1465252929. The cubic root of 18663666 is about 265.2562656881.

The spelling of 18663666 in words is "eighteen million, six hundred sixty-three thousand, six hundred sixty-six".