221303221 has 4 divisors (see below), whose sum is σ = 223494444. Its totient is φ = 219112000.

The previous prime is 221303209. The next prime is 221303227. The reversal of 221303221 is 122303122.

221303221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 170694225 + 50608996 = 13065^2 + 7114^2 .

It is a cyclic number.

It is not a de Polignac number, because 221303221 - 2⁵ = 221303189 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221303195 and 221303204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221303227) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1095460 + ... + 1095661.

It is an arithmetic number, because the mean of its divisors is an integer number (55873611).

Almost surely, 2^221303221 is an apocalyptic number.

It is an amenable number.

221303221 is a deficient number, since it is larger than the sum of its proper divisors (2191223).

221303221 is a wasteful number, since it uses less digits than its factorization.

221303221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2191222.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 221303221 is about 14876.2636774158. The cubic root of 221303221 is about 604.8707425978.

Adding to 221303221 its reverse (122303122), we get a palindrome (343606343).

Subtracting from 221303221 its reverse (122303122), we obtain a palindrome (99000099).

The spelling of 221303221 in words is "two hundred twenty-one million, three hundred three thousand, two hundred twenty-one".