18520866 has 64 divisors (see below), whose sum is σ = 50668800. Its totient is φ = 4883328.

The previous prime is 18520841. The next prime is 18520883. The reversal of 18520866 is 66802581.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 18520866.

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, 3030 + ... + 6798.

It is an arithmetic number, because the mean of its divisors is an integer number (791700).

Almost surely, 2^18520866 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18520866, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25334400).

18520866 is an abundant number, since it is smaller than the sum of its proper divisors (32147934).

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

18520866 is a wasteful number, since it uses less digits than its factorization.

18520866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3800 (or 3794 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 18520866 is about 4303.5875731766. The cubic root of 18520866 is about 264.5780207061.

The spelling of 18520866 in words is "eighteen million, five hundred twenty thousand, eight hundred sixty-six".