18273220 has 24 divisors (see below), whose sum is σ = 43856064. Its totient is φ = 6265056.

The previous prime is 18273209. The next prime is 18273239. The reversal of 18273220 is 2237281.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 65122 + ... + 65401.

It is an arithmetic number, because the mean of its divisors is an integer number (1827336).

Almost surely, 2^18273220 is an apocalyptic number.

18273220 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18273220 is an abundant number, since it is smaller than the sum of its proper divisors (25582844).

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

18273220 is a wasteful number, since it uses less digits than its factorization.

18273220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 130539 (or 130537 counting only the distinct ones).

The product of its (nonzero) digits is 1344, while the sum is 25.

The square root of 18273220 is about 4274.7187041956. The cubic root of 18273220 is about 263.3934844521.

The spelling of 18273220 in words is "eighteen million, two hundred seventy-three thousand, two hundred twenty".