221864256 has 84 divisors (see below), whose sum is σ = 663622752. Its totient is φ = 70735104.

The previous prime is 221864183. The next prime is 221864267. The reversal of 221864256 is 652468122.

It is a happy number.

221864256 is a `hidden beast` number, since 2 + 2 + 1 + 8 + 642 + 5 + 6 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 221864256.

It is a congruent number.

It is an unprimeable number.

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 11 ways as a sum of consecutive naturals, for example, 4875 + ... + 21621.

Almost surely, 2^221864256 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 221864256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (331811376).

221864256 is an abundant number, since it is smaller than the sum of its proper divisors (441758496).

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

221864256 is a wasteful number, since it uses less digits than its factorization.

221864256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16788 (or 16775 counting only the distinct ones).

The product of its digits is 46080, while the sum is 36.

The square root of 221864256 is about 14895.1084588196. The cubic root of 221864256 is about 605.3814555898.

The spelling of 221864256 in words is "two hundred twenty-one million, eight hundred sixty-four thousand, two hundred fifty-six".