18663720 has 64 divisors (see below), whose sum is σ = 57309120. Its totient is φ = 4859904.

The previous prime is 18663709. The next prime is 18663727. The reversal of 18663720 is 2736681.

It is a super-3 number, since 3×18663720³ (a number of 23 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (18663727) 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, 3352 + ... + 6968.

It is an arithmetic number, because the mean of its divisors is an integer number (895455).

Almost surely, 2^18663720 is an apocalyptic number.

18663720 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 18663720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28654560).

18663720 is an abundant number, since it is smaller than the sum of its proper divisors (38645400).

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

18663720 is a wasteful number, since it uses less digits than its factorization.

18663720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3674 (or 3670 counting only the distinct ones).

The product of its (nonzero) digits is 12096, while the sum is 33.

The square root of 18663720 is about 4320.1527750764. The cubic root of 18663720 is about 265.2565215118.

The spelling of 18663720 in words is "eighteen million, six hundred sixty-three thousand, seven hundred twenty".