18371220 has 192 divisors, whose sum is σ = 65028096. Its totient is φ = 3778560.

The previous prime is 18371209. The next prime is 18371257. The reversal of 18371220 is 2217381.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 221299 + ... + 221381.

It is an arithmetic number, because the mean of its divisors is an integer number (338688).

Almost surely, 2^18371220 is an apocalyptic number.

18371220 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 18371220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32514048).

18371220 is an abundant number, since it is smaller than the sum of its proper divisors (46656876).

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

18371220 is a wasteful number, since it uses less digits than its factorization.

18371220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 150 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 672, while the sum is 24.

The square root of 18371220 is about 4286.1661190393. The cubic root of 18371220 is about 263.8635084157.

The spelling of 18371220 in words is "eighteen million, three hundred seventy-one thousand, two hundred twenty".