221597856 has 240 divisors, whose sum is σ = 711317376. Its totient is φ = 67405824.

The previous prime is 221597821. The next prime is 221597861. The reversal of 221597856 is 658795122.

221597856 is a `hidden beast` number, since 2 + 2 + 1 + 597 + 8 + 56 = 666.

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 39 ways as a sum of consecutive naturals, for example, 2070955 + ... + 2071061.

Almost surely, 2^221597856 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 221597856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (355658688).

221597856 is an abundant number, since it is smaller than the sum of its proper divisors (489719520).

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

221597856 is a wasteful number, since it uses less digits than its factorization.

221597856 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 193 (or 176 counting only the distinct ones).

The product of its digits is 302400, while the sum is 45.

The square root of 221597856 is about 14886.1632397337. The cubic root of 221597856 is about 605.1390578062.

The spelling of 221597856 in words is "two hundred twenty-one million, five hundred ninety-seven thousand, eight hundred fifty-six".