18213228 has 48 divisors (see below), whose sum is σ = 51515520. Its totient is φ = 5518800.

The previous prime is 18213211. The next prime is 18213233. The reversal of 18213228 is 82231281.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6478 + ... + 8853.

It is an arithmetic number, because the mean of its divisors is an integer number (1073240).

Almost surely, 2^18213228 is an apocalyptic number.

18213228 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

18213228 is an abundant number, since it is smaller than the sum of its proper divisors (33302292).

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

18213228 is a wasteful number, since it uses less digits than its factorization.

18213228 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15355 (or 15347 counting only the distinct ones).

The product of its digits is 1536, while the sum is 27.

The square root of 18213228 is about 4267.6958654525. The cubic root of 18213228 is about 263.1049232692.

The spelling of 18213228 in words is "eighteen million, two hundred thirteen thousand, two hundred twenty-eight".