18205220 has 48 divisors (see below), whose sum is σ = 42251328. Its totient is φ = 6533760.

The previous prime is 18205183. The next prime is 18205237. The reversal of 18205220 is 2250281.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a junction number, because it is equal to n+sod(n) for n = 18205192 and 18205201.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 17762 + ... + 18758.

It is an arithmetic number, because the mean of its divisors is an integer number (880236).

Almost surely, 2^18205220 is an apocalyptic number.

18205220 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 18205220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21125664).

18205220 is an abundant number, since it is smaller than the sum of its proper divisors (24046108).

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

18205220 is a wasteful number, since it uses less digits than its factorization.

18205220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1100 (or 1098 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 18205220 is about 4266.7575511154. The cubic root of 18205220 is about 263.0663569207.

The spelling of 18205220 in words is "eighteen million, two hundred five thousand, two hundred twenty".