221382720 has 392 divisors, whose sum is σ = 862849176. Its totient is φ = 53747712.

The previous prime is 221382713. The next prime is 221382731. The reversal of 221382720 is 27283122.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 5645376 + 215737344 = 2376^2 + 14688^2 .

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 3032604 + ... + 3032676.

Almost surely, 2^221382720 is an apocalyptic number.

221382720 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 221382720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (431424588).

221382720 is an abundant number, since it is smaller than the sum of its proper divisors (641466456).

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

221382720 is an equidigital number, since it uses as much as digits as its factorization.

221382720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 121 (or 96 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 221382720 is about 14878.9354457905. The cubic root of 221382720 is about 604.9431633878.

The spelling of 221382720 in words is "two hundred twenty-one million, three hundred eighty-two thousand, seven hundred twenty".