221232144 has 80 divisors (see below), whose sum is σ = 655795328. Its totient is φ = 62954496.

The previous prime is 221232133. The next prime is 221232163. The reversal of 221232144 is 441232122.

221232144 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 (21).

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 221232144.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 91884 + ... + 94260.

Almost surely, 2^221232144 is an apocalyptic number.

221232144 is a gapful number since it is divisible by the number (24) 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 221232144, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (327897664).

221232144 is an abundant number, since it is smaller than the sum of its proper divisors (434563184).

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

221232144 is a wasteful number, since it uses less digits than its factorization.

221232144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2672 (or 2666 counting only the distinct ones).

The product of its digits is 768, while the sum is 21.

The square root of 221232144 is about 14873.8745456589. The cubic root of 221232144 is about 604.8059792668.

Adding to 221232144 its reverse (441232122), we get a palindrome (662464266).

The spelling of 221232144 in words is "two hundred twenty-one million, two hundred thirty-two thousand, one hundred forty-four".