221280444 has 288 divisors, whose sum is σ = 750758400. Its totient is φ = 55123200.

The previous prime is 221280439. The next prime is 221280457. The reversal of 221280444 is 444082122.

221280444 is a `hidden beast` number, since 2 + 212 + 8 + 0 + 444 = 666.

221280444 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3750487 + ... + 3750545.

It is an arithmetic number, because the mean of its divisors is an integer number (2606800).

Almost surely, 2^221280444 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 221280444, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (375379200).

221280444 is an abundant number, since it is smaller than the sum of its proper divisors (529477956).

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

221280444 is a wasteful number, since it uses less digits than its factorization.

221280444 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142 (or 123 counting only the distinct ones).

The product of its (nonzero) digits is 4096, while the sum is 27.

The square root of 221280444 is about 14875.4981093071. The cubic root of 221280444 is about 604.8499903564.

The spelling of 221280444 in words is "two hundred twenty-one million, two hundred eighty thousand, four hundred forty-four".