221144220 has 144 divisors (see below), whose sum is σ = 743154048. Its totient is φ = 52778880.

The previous prime is 221144207. The next prime is 221144221. The reversal of 221144220 is 22441122.

221144220 is a `hidden beast` number, since 221 + 1 + 442 + 2 + 0 = 666.

221144220 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a junction number, because it is equal to n+sod(n) for n = 221144193 and 221144202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221144221) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 131827 + ... + 133493.

It is an arithmetic number, because the mean of its divisors is an integer number (5160792).

Almost surely, 2^221144220 is an apocalyptic number.

221144220 is a gapful number since it is divisible by the number (20) 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 221144220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (371577024).

221144220 is an abundant number, since it is smaller than the sum of its proper divisors (522009828).

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

221144220 is a wasteful number, since it uses less digits than its factorization.

221144220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1760 (or 1755 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 18.

The square root of 221144220 is about 14870.9185997369. The cubic root of 221144220 is about 604.7258462352.

Adding to 221144220 its reverse (22441122), we get a palindrome (243585342).

It can be divided in two parts, 221 and 144220, that added together give a palindrome (144441).

The spelling of 221144220 in words is "two hundred twenty-one million, one hundred forty-four thousand, two hundred twenty".