221331320 has 128 divisors (see below), whose sum is σ = 602173440. Its totient is φ = 71608320.

The previous prime is 221331293. The next prime is 221331337. The reversal of 221331320 is 23133122.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 372944 + ... + 373536.

It is an arithmetic number, because the mean of its divisors is an integer number (4704480).

Almost surely, 2^221331320 is an apocalyptic number.

221331320 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 221331320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (301086720).

221331320 is an abundant number, since it is smaller than the sum of its proper divisors (380842120).

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

221331320 is a wasteful number, since it uses less digits than its factorization.

221331320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 685 (or 681 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 17.

The square root of 221331320 is about 14877.2080714091. The cubic root of 221331320 is about 604.8963417789.

Adding to 221331320 its reverse (23133122), we get a palindrome (244464442).

It can be divided in two parts, 2213 and 31320, that added together give a palindrome (33533).

The spelling of 221331320 in words is "two hundred twenty-one million, three hundred thirty-one thousand, three hundred twenty".