18981018 has 48 divisors (see below), whose sum is σ = 47299200. Its totient is φ = 5388768.

The previous prime is 18980989. The next prime is 18981023. The reversal of 18981018 is 81018981.

It is an alternating number because its digits alternate between odd and even.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 24696 + ... + 25452.

It is an arithmetic number, because the mean of its divisors is an integer number (985400).

Almost surely, 2^18981018 is an apocalyptic number.

18981018 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 18981018, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23649600).

18981018 is an abundant number, since it is smaller than the sum of its proper divisors (28318182).

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

18981018 is a wasteful number, since it uses less digits than its factorization.

18981018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 971 (or 968 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 36.

The square root of 18981018 is about 4356.7210147082. The cubic root of 18981018 is about 266.7512728067.

Adding to 18981018 its reverse (81018981), we get a palindrome (99999999).

It can be divided in two parts, 1898 and 1018, that added together give a square (2916 = 54²).

The spelling of 18981018 in words is "eighteen million, nine hundred eighty-one thousand, eighteen".