18220784 has 40 divisors (see below), whose sum is σ = 37438080. Its totient is φ = 8572608.

The previous prime is 18220781. The next prime is 18220789. The reversal of 18220784 is 48702281.

It is a self number, because there is not a number n which added to its sum of digits gives 18220784.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18220781) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 24287 + ... + 25025.

It is an arithmetic number, because the mean of its divisors is an integer number (935952).

Almost surely, 2^18220784 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 18220784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (18719040).

18220784 is an abundant number, since it is smaller than the sum of its proper divisors (19217296).

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

18220784 is a wasteful number, since it uses less digits than its factorization.

18220784 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 837 (or 831 counting only the distinct ones).

The product of its (nonzero) digits is 7168, while the sum is 32.

The square root of 18220784 is about 4268.5810288666. The cubic root of 18220784 is about 263.1413024318.

The spelling of 18220784 in words is "eighteen million, two hundred twenty thousand, seven hundred eighty-four".