18402228 has 120 divisors (see below), whose sum is σ = 55068552. Its totient is φ = 5308416.

The previous prime is 18402227. The next prime is 18402229. The reversal of 18402228 is 82220481.

It is an interprime number because it is at equal distance from previous prime (18402227) and next prime (18402229).

It can be written as a sum of positive squares in 4 ways, for example, as 7193124 + 11209104 = 2682^2 + 3348^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18402227) by changing a digit.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 71476 + ... + 71732.

Almost surely, 2^18402228 is an apocalyptic number.

18402228 is a gapful number since it is divisible by the number (18) 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 18402228, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27534276).

18402228 is an abundant number, since it is smaller than the sum of its proper divisors (36666324).

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

18402228 is a wasteful number, since it uses less digits than its factorization.

18402228 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 303 (or 292 counting only the distinct ones).

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

The square root of 18402228 is about 4289.7818126334. The cubic root of 18402228 is about 264.0118796307.

The spelling of 18402228 in words is "eighteen million, four hundred two thousand, two hundred twenty-eight".