221465720 has 64 divisors (see below), whose sum is σ = 584902080. Its totient is φ = 73875456.

The previous prime is 221465719. The next prime is 221465773. The reversal of 221465720 is 27564122.

It is a happy number.

221465720 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

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, 329 + ... + 21048.

It is an arithmetic number, because the mean of its divisors is an integer number (9139095).

Almost surely, 2^221465720 is an apocalyptic number.

221465720 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 221465720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (292451040).

221465720 is an abundant number, since it is smaller than the sum of its proper divisors (363436360).

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

221465720 is a wasteful number, since it uses less digits than its factorization.

221465720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21432 (or 21428 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 29.

The square root of 221465720 is about 14881.7243624521. The cubic root of 221465720 is about 605.0187549681.

The spelling of 221465720 in words is "two hundred twenty-one million, four hundred sixty-five thousand, seven hundred twenty".