221031018 has 40 divisors (see below), whose sum is σ = 533376228. Its totient is φ = 68008896.

The previous prime is 221031017. The next prime is 221031043. The reversal of 221031018 is 810130122.

221031018 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 195356529 + 25674489 = 13977^2 + 5067^2 .

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (221031017) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 50371 + ... + 54582.

Almost surely, 2^221031018 is an apocalyptic number.

221031018 is an abundant number, since it is smaller than the sum of its proper divisors (312345210).

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

221031018 is a wasteful number, since it uses less digits than its factorization.

221031018 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104980 (or 104971 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 18.

The square root of 221031018 is about 14867.1119589515. Note that the first 3 decimals coincide. The cubic root of 221031018 is about 604.6226438102.

The spelling of 221031018 in words is "two hundred twenty-one million, thirty-one thousand, eighteen".