221311320 has 64 divisors (see below), whose sum is σ = 670813920. Its totient is φ = 58404864.

The previous prime is 221311303. The next prime is 221311351. The reversal of 221311320 is 23113122.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 221311320.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2134 + ... + 21146.

Almost surely, 2^221311320 is an apocalyptic number.

221311320 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 221311320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (335406960).

221311320 is an abundant number, since it is smaller than the sum of its proper divisors (449502600).

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

221311320 is a wasteful number, since it uses less digits than its factorization.

221311320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19124 (or 19120 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

The square root of 221311320 is about 14876.5358870941. The cubic root of 221311320 is about 604.8781212950.

Adding to 221311320 its reverse (23113122), we get a palindrome (244424442).

The spelling of 221311320 in words is "two hundred twenty-one million, three hundred eleven thousand, three hundred twenty".