18668640 has 192 divisors, whose sum is σ = 65318400. Its totient is φ = 4460544.

The previous prime is 18668599. The next prime is 18668641. The reversal of 18668640 is 4686681.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18668641) 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 31 ways as a sum of consecutive naturals, for example, 209716 + ... + 209804.

It is an arithmetic number, because the mean of its divisors is an integer number (340200).

Almost surely, 2^18668640 is an apocalyptic number.

18668640 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18668640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32659200).

18668640 is an abundant number, since it is smaller than the sum of its proper divisors (46649760).

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

18668640 is a wasteful number, since it uses less digits than its factorization.

18668640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149 (or 141 counting only the distinct ones).

The product of its (nonzero) digits is 55296, while the sum is 39.

The square root of 18668640 is about 4320.7221618614. The cubic root of 18668640 is about 265.2798278235.

The spelling of 18668640 in words is "eighteen million, six hundred sixty-eight thousand, six hundred forty".