18681666 has 8 divisors (see below), whose sum is σ = 37363344. Its totient is φ = 6227220.

The previous prime is 18681661. The next prime is 18681671. The reversal of 18681666 is 66618681.

It is an interprime number because it is at equal distance from previous prime (18681661) and next prime (18681671).

It is a sphenic number, since it is the product of 3 distinct primes.

18681666 is an admirable number.

It is not an unprimeable number, because it can be changed into a prime (18681661) 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 3 ways as a sum of consecutive naturals, for example, 1556800 + ... + 1556811.

It is an arithmetic number, because the mean of its divisors is an integer number (4670418).

Almost surely, 2^18681666 is an apocalyptic number.

18681666 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

18681666 is a wasteful number, since it uses less digits than its factorization.

18681666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3113616.

The product of its digits is 82944, while the sum is 42.

The square root of 18681666 is about 4322.2292859125. The cubic root of 18681666 is about 265.3415129391.

The spelling of 18681666 in words is "eighteen million, six hundred eighty-one thousand, six hundred sixty-six".