18042228 has 18 divisors (see below), whose sum is σ = 45606834. Its totient is φ = 6014064.

The previous prime is 18042221. The next prime is 18042239. The reversal of 18042228 is 82224081.

It can be written as a sum of positive squares in only one way, i.e., 11009124 + 7033104 = 3318^2 + 2652^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18042221) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 250551 + ... + 250622.

It is an arithmetic number, because the mean of its divisors is an integer number (2533713).

Almost surely, 2^18042228 is an apocalyptic number.

18042228 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

18042228 is an abundant number, since it is smaller than the sum of its proper divisors (27564606).

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

18042228 is a wasteful number, since it uses less digits than its factorization.

18042228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 501183 (or 501178 counting only the distinct ones).

The product of its (nonzero) digits is 2048, while the sum is 27.

The square root of 18042228 is about 4247.6143892778. The cubic root of 18042228 is about 262.2789213418.

The spelling of 18042228 in words is "eighteen million, forty-two thousand, two hundred twenty-eight".