221864320 has 64 divisors (see below), whose sum is σ = 539184240. Its totient is φ = 87275520.

The previous prime is 221864267. The next prime is 221864323. The reversal of 221864320 is 23468122.

It is a tau number, because it is divible by the number of its divisors (64).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221864323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 36199 + ... + 41881.

Almost surely, 2^221864320 is an apocalyptic number.

221864320 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 221864320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (269592120).

221864320 is an abundant number, since it is smaller than the sum of its proper divisors (317319920).

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

221864320 is an equidigital number, since it uses as much as digits as its factorization.

221864320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5763 (or 5751 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 28.

The square root of 221864320 is about 14895.1106071758. The cubic root of 221864320 is about 605.3815138002.

The spelling of 221864320 in words is "two hundred twenty-one million, eight hundred sixty-four thousand, three hundred twenty".