18228978 has 12 divisors (see below), whose sum is σ = 39496158. Its totient is φ = 6076320.

The previous prime is 18228971. The next prime is 18228983. The reversal of 18228978 is 87982281.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18122049 + 106929 = 4257^2 + 327^2 .

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18228971) 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, 506343 + ... + 506378.

Almost surely, 2^18228978 is an apocalyptic number.

18228978 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18228978 is an abundant number, since it is smaller than the sum of its proper divisors (21267180).

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

18228978 is a wasteful number, since it uses less digits than its factorization.

18228978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1012729 (or 1012726 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 18228978 is about 4269.5407247150. The cubic root of 18228978 is about 263.1807419476.

The spelling of 18228978 in words is "eighteen million, two hundred twenty-eight thousand, nine hundred seventy-eight".