220221 has 6 divisors (see below), whose sum is σ = 318110. Its totient is φ = 146808.

The previous prime is 220217. The next prime is 220243. The reversal of 220221 is 122022.

It can be written as a sum of positive squares in only one way, i.e., 152100 + 68121 = 390^2 + 261^2 .

It is not a de Polignac number, because 220221 - 2² = 220217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (9), and also a Moran number because the ratio is a prime number: 24469 = 220221 / (2 + 2 + 0 + 2 + 2 + 1).

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (220291) by changing a digit.

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 5 ways as a sum of consecutive naturals, for example, 12226 + ... + 12243.

2²²⁰²²¹ is an apocalyptic number.

It is an amenable number.

220221 is a deficient number, since it is larger than the sum of its proper divisors (97889).

220221 is a wasteful number, since it uses less digits than its factorization.

220221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24475 (or 24472 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 9.

The square root of 220221 is about 469.2771036392. The cubic root of 220221 is about 60.3883147724.

Adding to 220221 its reverse (122022), we get a palindrome (342243).

It can be divided in two parts, 220 and 221, that added together give a square (441 = 21²).

The spelling of 220221 in words is "two hundred twenty thousand, two hundred twenty-one", and thus it is an iban number.