18020864 has 40 divisors (see below), whose sum is σ = 36660228. Its totient is φ = 8847360.

The previous prime is 18020851. The next prime is 18020897. The reversal of 18020864 is 46802081.

It can be written as a sum of positive squares in 2 ways, for example, as 17977600 + 43264 = 4240^2 + 208^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30944 + ... + 31520.

Almost surely, 2^18020864 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18020864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18330114).

18020864 is an abundant number, since it is smaller than the sum of its proper divisors (18639364).

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

18020864 is an frugal number, since it uses more digits than its factorization.

18020864 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 656 (or 640 counting only the distinct ones).

The product of its (nonzero) digits is 3072, while the sum is 29.

The square root of 18020864 is about 4245.0988209935. The cubic root of 18020864 is about 262.1753580054.

The spelling of 18020864 in words is "eighteen million, twenty thousand, eight hundred sixty-four".