18660816 has 30 divisors (see below), whose sum is σ = 52224770. Its totient is φ = 6220224.

The previous prime is 18660809. The next prime is 18660821. The reversal of 18660816 is 61806681.

It can be written as a sum of positive squares in only one way, i.e., 13838400 + 4822416 = 3720^2 + 2196^2 .

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 (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 64651 + ... + 64938.

Almost surely, 2^18660816 is an apocalyptic number.

18660816 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

18660816 is an abundant number, since it is smaller than the sum of its proper divisors (33563954).

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

18660816 is a wasteful number, since it uses less digits than its factorization.

18660816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 129603 (or 129594 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 36.

The square root of 18660816 is about 4319.8166627763. The cubic root of 18660816 is about 265.2427631812.

It can be divided in two parts, 186608 and 16, that added together give a square (186624 = 432²).

The spelling of 18660816 in words is "eighteen million, six hundred sixty thousand, eight hundred sixteen".