18722220 has 96 divisors (see below), whose sum is σ = 60238080. Its totient is φ = 4296960.

The previous prime is 18722191. The next prime is 18722267. The reversal of 18722220 is 2222781.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 11794 + ... + 13286.

It is an arithmetic number, because the mean of its divisors is an integer number (627480).

Almost surely, 2^18722220 is an apocalyptic number.

18722220 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 18722220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30119040).

18722220 is an abundant number, since it is smaller than the sum of its proper divisors (41515860).

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

18722220 is a wasteful number, since it uses less digits than its factorization.

18722220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1535 (or 1533 counting only the distinct ones).

The product of its (nonzero) digits is 896, while the sum is 24.

The square root of 18722220 is about 4326.9180717920. The cubic root of 18722220 is about 265.5333745342.

The spelling of 18722220 in words is "eighteen million, seven hundred twenty-two thousand, two hundred twenty".