18666720 has 192 divisors, whose sum is σ = 68040000. Its totient is φ = 4773888.

The previous prime is 18666709. The next prime is 18666733. The reversal of 18666720 is 2766681.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

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, 125206 + ... + 125354.

It is an arithmetic number, because the mean of its divisors is an integer number (354375).

Almost surely, 2^18666720 is an apocalyptic number.

18666720 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a pronic number, being equal to 4320×4321.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18666720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34020000).

18666720 is an abundant number, since it is smaller than the sum of its proper divisors (49373280).

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

18666720 is a wasteful number, since it uses less digits than its factorization.

18666720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202 (or 188 counting only the distinct ones).

The product of its (nonzero) digits is 24192, while the sum is 36.

The square root of 18666720 is about 4320.4999710682. The cubic root of 18666720 is about 265.2707331647.

It can be divided in two parts, 18666 and 720, that multiplied together give a triangular number (13439520 = T₅₁₈₄).

The spelling of 18666720 in words is "eighteen million, six hundred sixty-six thousand, seven hundred twenty".