221556 has 24 divisors (see below), whose sum is σ = 532000. Its totient is φ = 71712.

The previous prime is 221549. The next prime is 221567. The reversal of 221556 is 655122.

221556 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a super-2 number, since 2×221556² = 98174122272, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

221556 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 195 + ... + 693.

2²²¹⁵⁵⁶ is an apocalyptic number.

It is an amenable number.

221556 is an abundant number, since it is smaller than the sum of its proper divisors (310444).

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

221556 is a wasteful number, since it uses less digits than its factorization.

221556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 543 (or 541 counting only the distinct ones).

The product of its digits is 600, while the sum is 21.

The square root of 221556 is about 470.6973549958. The cubic root of 221556 is about 60.5100955309.

Adding to 221556 its reverse (655122), we get a palindrome (876678).

It can be divided in two parts, 221 and 556, that added together give a palindrome (777).

The spelling of 221556 in words is "two hundred twenty-one thousand, five hundred fifty-six".