221988018 has 32 divisors (see below), whose sum is σ = 514980864. Its totient is φ = 62477712.

The previous prime is 221988017. The next prime is 221988029. The reversal of 221988018 is 810889122.

221988018 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not an unprimeable number, because it can be changed into a prime (221988017) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 36630 + ... + 42257.

It is an arithmetic number, because the mean of its divisors is an integer number (16093152).

Almost surely, 2^221988018 is an apocalyptic number.

221988018 is an abundant number, since it is smaller than the sum of its proper divisors (292992846).

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

221988018 is a wasteful number, since it uses less digits than its factorization.

221988018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 78966.

The product of its (nonzero) digits is 18432, while the sum is 39.

The square root of 221988018 is about 14899.2623307330. The cubic root of 221988018 is about 605.4940008220.

The spelling of 221988018 in words is "two hundred twenty-one million, nine hundred eighty-eight thousand, eighteen".